[PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Baolin Wang]

This patch adds the binding documentation for Spreadtrum I2C
controller device.

Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
---
Changes since v2:
 - Change compatible strings to be SoC specific.

Changes since v1:
 - No updates.
---
 Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sprd.txt b/Documentation/devicetree/bindings/i2c/i2c-sprd.txt
new file mode 100644
index 0000000..60b7cda
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-sprd.txt
@@ -0,0 +1,31 @@
+I2C for Spreadtrum platforms
+
+Required properties:
+- compatible: Should be "sprd,sc9860-i2c".
+- reg: Specify the physical base address of the controller and length
+  of memory mapped region.
+- interrupts: Should contain I2C interrupt.
+- clock-names: Should contain following entries:
+  "i2c" for I2C clock,
+  "source" for I2C source (parent) clock,
+  "enable" for I2C module enable clock.
+- clocks: Should contain a clock specifier for each entry in clock-names.
+- clock-frequency: Constains desired I2C bus clock frequency in Hz.
+- #address-cells: Should be 1 to describe address cells for I2C device address.
+- #size-cells: Should be 0 means no size cell for I2C device address.
+
+Optional properties:
+- Child nodes conforming to I2C bus binding
+
+Examples:
+i2c0: i2c@70500000 {
+	compatible = "sprd,sc9860-i2c";
+	reg = <0 0x70500000 0 0x1000>;
+	interrupts = <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>;
+	clock-names = "i2c", "source", "enable";
+	clocks = <&clk_i2c3>, <&ext_26m>, <&clk_ap_apb_gates 11>;
+	clock-frequency = <400000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+};
+
-- 
1.7.9.5

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[PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Baolin Wang]

This patch adds the binding documentation for Spreadtrum I2C
controller device.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
---
Changes since v2:
 - Change compatible strings to be SoC specific.

Changes since v1:
 - No updates.
---
 Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sprd.txt b/Documentation/devicetree/bindings/i2c/i2c-sprd.txt
new file mode 100644
index 0000000..60b7cda
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-sprd.txt
@@ -0,0 +1,31 @@
+I2C for Spreadtrum platforms
+
+Required properties:
+- compatible: Should be "sprd,sc9860-i2c".
+- reg: Specify the physical base address of the controller and length
+  of memory mapped region.
+- interrupts: Should contain I2C interrupt.
+- clock-names: Should contain following entries:
+  "i2c" for I2C clock,
+  "source" for I2C source (parent) clock,
+  "enable" for I2C module enable clock.
+- clocks: Should contain a clock specifier for each entry in clock-names.
+- clock-frequency: Constains desired I2C bus clock frequency in Hz.
+- #address-cells: Should be 1 to describe address cells for I2C device address.
+- #size-cells: Should be 0 means no size cell for I2C device address.
+
+Optional properties:
+- Child nodes conforming to I2C bus binding
+
+Examples:
+i2c0: i2c@70500000 {
+	compatible = "sprd,sc9860-i2c";
+	reg = <0 0x70500000 0 0x1000>;
+	interrupts = <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>;
+	clock-names = "i2c", "source", "enable";
+	clocks = <&clk_i2c3>, <&ext_26m>, <&clk_ap_apb_gates 11>;
+	clock-frequency = <400000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+};
+
-- 
1.7.9.5

[PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

This patch adds the I2C controller driver for Spreadtrum SC9860 platform.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
---
Changes since v2:
 - Remove some redundant comments and parens.
 - Define macros instead of magic number.
 - Add some comments to explain clock formula.
 - Change of_clk_get_by_name() to devm_clk_get().
 - Deal with other frequency.
 - Change register definiton to low case.
 - Change is_last_msg to boolean.
 - Other optimization.

Changes sice v1:
 - Power on I2C device in probe().
 - Remove redundant macros and usb __maybe_unused.
 - Remove redundant 'of_match_ptr'.
 - Modify return values and check the return value for 'clk_prepare_enable'.
---
 drivers/i2c/busses/Kconfig    |    7 +
 drivers/i2c/busses/Makefile   |    1 +
 drivers/i2c/busses/i2c-sprd.c |  683 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 691 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-sprd.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 8adc0f1..86476b9 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -877,6 +877,13 @@ config I2C_SIRF
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-sirf.
 
+config I2C_SPRD
+	bool "Spreadtrum I2C interface"
+	depends on ARCH_SPRD
+	help
+	  If you say yes to this option, support will be included for the
+	  Spreadtrum I2C interface.
+
 config I2C_ST
 	tristate "STMicroelectronics SSC I2C support"
 	depends on ARCH_STI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 30b6085..dd46c21 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
 obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
+obj-$(CONFIG_I2C_SPRD)		+= i2c-sprd.o
 obj-$(CONFIG_I2C_ST)		+= i2c-st.o
 obj-$(CONFIG_I2C_STM32F4)	+= i2c-stm32f4.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
new file mode 100644
index 0000000..a070f61
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sprd.c
@@ -0,0 +1,683 @@
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#define I2C_CTL			0x00
+#define I2C_ADDR_CFG		0x04
+#define I2C_COUNT		0x08
+#define I2C_RX			0x0c
+#define I2C_TX			0x10
+#define I2C_STATUS		0x14
+#define I2C_HSMODE_CFG		0x18
+#define I2C_VERSION		0x1c
+#define ADDR_DVD0		0x20
+#define ADDR_DVD1		0x24
+#define ADDR_STA0_DVD		0x28
+#define ADDR_RST		0x2c
+
+/* I2C_CTL */
+#define STP_EN			BIT(20)
+#define FIFO_AF_LVL_MASK	GENMASK(19, 16)
+#define FIFO_AF_LVL		16
+#define FIFO_AE_LVL_MASK	GENMASK(15, 12)
+#define FIFO_AE_LVL		12
+#define I2C_DMA_EN		BIT(11)
+#define FULL_INTEN		BIT(10)
+#define EMPTY_INTEN		BIT(9)
+#define I2C_DVD_OPT		BIT(8)
+#define I2C_OUT_OPT		BIT(7)
+#define I2C_TRIM_OPT		BIT(6)
+#define I2C_HS_MODE		BIT(4)
+#define I2C_MODE		BIT(3)
+#define I2C_EN			BIT(2)
+#define I2C_INT_EN		BIT(1)
+#define I2C_START		BIT(0)
+
+/* I2C_STATUS */
+#define SDA_IN			BIT(21)
+#define SCL_IN			BIT(20)
+#define FIFO_FULL		BIT(4)
+#define FIFO_EMPTY		BIT(3)
+#define I2C_INT			BIT(2)
+#define I2C_RX_ACK		BIT(1)
+#define I2C_BUSY		BIT(0)
+
+/* ADDR_RST */
+#define I2C_RST			BIT(0)
+
+#define I2C_FIFO_DEEP		12
+#define I2C_FIFO_FULL_THLD	15
+#define I2C_FIFO_EMPTY_THLD	4
+#define I2C_DATA_STEP		8
+#define I2C_ADDR_DVD0_CALC(high, low)	\
+	((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0)))
+#define I2C_ADDR_DVD1_CALC(high, low)	\
+	(((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16))
+
+/* timeout (ms) for pm runtime autosuspend */
+#define SPRD_I2C_PM_TIMEOUT	1000
+
+/* SPRD i2c data structure */
+struct sprd_i2c {
+	struct i2c_adapter adap;
+	struct device *dev;
+	void __iomem *base;
+	struct i2c_msg *msg;
+	struct clk *clk;
+	unsigned int src_clk;
+	unsigned int bus_freq;
+	struct completion complete;
+	u8 *buf;
+	u16 count;
+	int irq;
+	int err;
+};
+
+static void sprd_i2c_dump_reg(struct sprd_i2c *i2c_dev)
+{
+	dev_err(&i2c_dev->adap.dev, ": ======dump i2c-%d reg=======\n",
+		i2c_dev->adap.nr);
+	dev_err(&i2c_dev->adap.dev, ": I2C_CTRL:0x%x\n",
+		readl(i2c_dev->base + I2C_CTL));
+	dev_err(&i2c_dev->adap.dev, ": I2C_ADDR_CFG:0x%x\n",
+		readl(i2c_dev->base + I2C_ADDR_CFG));
+	dev_err(&i2c_dev->adap.dev, ": I2C_COUNT:0x%x\n",
+		readl(i2c_dev->base + I2C_COUNT));
+	dev_err(&i2c_dev->adap.dev, ": I2C_RX:0x%x\n",
+		readl(i2c_dev->base + I2C_RX));
+	dev_err(&i2c_dev->adap.dev, ": I2C_STATUS:0x%x\n",
+		readl(i2c_dev->base + I2C_STATUS));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_DVD0:0x%x\n",
+		readl(i2c_dev->base + ADDR_DVD0));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_DVD1:0x%x\n",
+		readl(i2c_dev->base + ADDR_DVD1));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_STA0_DVD:0x%x\n",
+		readl(i2c_dev->base + ADDR_STA0_DVD));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_RST:0x%x\n",
+		readl(i2c_dev->base + ADDR_RST));
+}
+
+static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
+{
+	writel(count, i2c_dev->base + I2C_COUNT);
+}
+
+static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (stop)
+		writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL);
+	else
+		writel(tmp | STP_EN, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_STATUS);
+
+	writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS);
+}
+
+static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_STATUS);
+
+	writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS);
+}
+
+static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev)
+{
+	writel(I2C_RST, i2c_dev->base + ADDR_RST);
+}
+
+static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m)
+{
+	writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG);
+}
+
+static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
+{
+	u32 i;
+
+	for (i = 0; i < len; i++)
+		writeb(buf[i], i2c_dev->base + I2C_TX);
+}
+
+static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u16 len)
+{
+	u32 i;
+
+	for (i = 0; i < len; i++)
+		buf[i] = readb(i2c_dev->base + I2C_RX);
+}
+
+static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	tmp &= ~FIFO_AF_LVL_MASK;
+	tmp |= full_thld << FIFO_AF_LVL;
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	tmp &= ~FIFO_AE_LVL_MASK;
+	tmp |= empty_thld << FIFO_AE_LVL;
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (enable)
+		tmp |= FULL_INTEN;
+	else
+		tmp &= ~FULL_INTEN;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (enable)
+		tmp |= EMPTY_INTEN;
+	else
+		tmp &= ~EMPTY_INTEN;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	writel(tmp | I2C_START, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw)
+{
+	unsigned int cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE;
+
+	writel(cmd | rw << 3, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev)
+{
+	u32 i2c_count = i2c_dev->count;
+	u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP;
+	struct i2c_msg *msg = i2c_dev->msg;
+
+	if (msg->flags & I2C_M_RD) {
+		sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD);
+		i2c_dev->count -= I2C_FIFO_FULL_THLD;
+		i2c_dev->buf += I2C_FIFO_FULL_THLD;
+
+		/*
+		 * If the read data count is larger than rx fifo full threshold,
+		 * we should enable the rx fifo full interrupt to read data
+		 * again.
+		 */
+		if (i2c_dev->count >= I2C_FIFO_FULL_THLD)
+			sprd_i2c_set_fifo_full_int(i2c_dev, 1);
+	} else {
+		sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran);
+		i2c_dev->buf += need_tran;
+		i2c_dev->count -= need_tran;
+
+		/*
+		 * If the write data count is arger than tx fifo depth which
+		 * means we can not write all data in one time, then we should
+		 * enable the tx fifo empty interrupt to write again.
+		 */
+		if (i2c_count > I2C_FIFO_DEEP)
+			sprd_i2c_set_fifo_empty_int(i2c_dev, 1);
+	}
+}
+
+static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
+			       struct i2c_msg *msg, bool is_last_msg)
+{
+	struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
+
+	i2c_dev->msg = msg;
+	i2c_dev->buf = msg->buf;
+	i2c_dev->count = msg->len;
+
+	reinit_completion(&i2c_dev->complete);
+	sprd_i2c_reset_fifo(i2c_dev);
+	sprd_i2c_set_devaddr(i2c_dev, msg);
+	sprd_i2c_set_count(i2c_dev, msg->len);
+
+	if ((msg->flags & I2C_M_RD)) {
+		sprd_i2c_opt_mode(i2c_dev, 1);
+		sprd_i2c_send_stop(i2c_dev, 1);
+	} else {
+		sprd_i2c_opt_mode(i2c_dev, 0);
+		sprd_i2c_send_stop(i2c_dev, !!is_last_msg);
+	}
+
+	/*
+	 * We should enable rx fifo full interrupt to get data when receiving
+	 * full data.
+	 */
+	if ((msg->flags & I2C_M_RD))
+		sprd_i2c_set_fifo_full_int(i2c_dev, 1);
+	else
+		sprd_i2c_data_transfer(i2c_dev);
+
+	sprd_i2c_opt_start(i2c_dev);
+
+	wait_for_completion(&i2c_dev->complete);
+
+	return i2c_dev->err;
+}
+
+static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
+				struct i2c_msg *msgs, int num)
+{
+	struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
+	int im, ret;
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0)
+		return ret;
+
+	for (im = 0; im < num - 1; im++) {
+		ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
+		if (ret)
+			goto err_msg;
+	}
+
+	ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1);
+
+err_msg:
+	pm_runtime_mark_last_busy(i2c_dev->dev);
+	pm_runtime_put_autosuspend(i2c_dev->dev);
+
+	return ret < 0 ? ret : im;
+}
+
+static u32 sprd_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm sprd_i2c_algo = {
+	.master_xfer = sprd_i2c_master_xfer,
+	.functionality = sprd_i2c_func,
+};
+
+static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, unsigned int freq)
+{
+	u32 apb_clk = i2c_dev->src_clk;
+	/*
+	 * From I2C databook, the prescale calculation formula:
+	 * prescale = freq_i2c / (4 * freq_scl) - 1;
+	 */
+	u32 i2c_dvd = apb_clk / (4 * freq) - 1;
+	/*
+	 * From I2C databook, the high period of SCL clock is recommended as
+	 * 40% (2/5), and the low period of SCL clock is recommended as 60%
+	 * (3/5), then the formula should be:
+	 * high = (prescale * 2 * 2) / 5
+	 * low = (prescale * 2 * 3) / 5
+	 */
+	u32 high = ((i2c_dvd << 1) * 2) / 5;
+	u32 low = ((i2c_dvd << 1) * 3) / 5;
+	u32 div0 = I2C_ADDR_DVD0_CALC(high, low);
+	u32 div1 = I2C_ADDR_DVD1_CALC(high, low);
+
+	writel(div0, i2c_dev->base + ADDR_DVD0);
+	writel(div1, i2c_dev->base + ADDR_DVD1);
+
+	/* Start hold timing = hold time(us) * source clock */
+	if (freq == 400000)
+		writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD);
+	else if (freq == 100000)
+		writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD);
+}
+
+static void sprd_i2c_enable(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = I2C_DVD_OPT;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+
+	sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD);
+	sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD);
+
+	sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq);
+	sprd_i2c_reset_fifo(i2c_dev);
+	sprd_i2c_clear_irq(i2c_dev);
+
+	tmp = readl(i2c_dev->base + I2C_CTL);
+	writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL);
+}
+
+static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id)
+{
+	struct sprd_i2c *i2c_dev = dev_id;
+	struct i2c_msg *msg = i2c_dev->msg;
+	int ack = readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK;
+	u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
+	u32 i2c_tran;
+
+	if (msg->flags & I2C_M_RD)
+		i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
+	else
+		i2c_tran = i2c_count;
+
+	/*
+	 * If we got one ACK from slave when writing data, and we did not
+	 * finish this transmission (i2c_tran is not zero), then we should
+	 * continue to write data.
+	 *
+	 * For reading data, ack is always 0, if i2c_tran is not 0 which
+	 * means we still need to contine to read data from slave.
+	 */
+	if (i2c_tran && !ack) {
+		sprd_i2c_data_transfer(i2c_dev);
+		return IRQ_HANDLED;
+	}
+
+	i2c_dev->err = 0;
+
+	/*
+	 * If we did not get one ACK from slave when writing data, we should
+	 * dump all registers to check I2C status.
+	 */
+	if (ack) {
+		i2c_dev->err = -EIO;
+		sprd_i2c_dump_reg(i2c_dev);
+	} else if (msg->flags & I2C_M_RD && i2c_dev->count) {
+		sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count);
+	}
+
+	/* Transmission is done and clear ack and start operation */
+	sprd_i2c_clear_ack(i2c_dev);
+	sprd_i2c_clear_start(i2c_dev);
+	complete(&i2c_dev->complete);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t sprd_i2c_isr(int irq, void *dev_id)
+{
+	struct sprd_i2c *i2c_dev = dev_id;
+	struct i2c_msg *msg = i2c_dev->msg;
+	u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
+	int ack = readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK;
+	u32 i2c_tran;
+
+	if (msg->flags & I2C_M_RD)
+		i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
+	else
+		i2c_tran = i2c_count;
+
+	/*
+	 * If ack == 0 means we got one ACK, if ack != 0 means we did not
+	 * get one ACK from slave when writing data, then we should finish
+	 * this transmission since we got some errors.
+	 *
+	 * When writing data, if i2c_tran == 0 which means we have writen
+	 * done all data, then we can finish this transmission.
+	 *
+	 * When reading data, if conut < rx fifo full threshold, which
+	 * means we can read all data in one time, then we can finish this
+	 * transmission too.
+	 */
+	if (!i2c_tran || ack) {
+		sprd_i2c_clear_start(i2c_dev);
+		sprd_i2c_clear_irq(i2c_dev);
+	}
+
+	sprd_i2c_set_fifo_empty_int(i2c_dev, 0);
+	sprd_i2c_set_fifo_full_int(i2c_dev, 0);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev)
+{
+	struct clk *clk_i2c, *clk_parent;
+
+	clk_i2c = devm_clk_get(i2c_dev->dev, "i2c");
+	if (IS_ERR(clk_i2c)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n",
+			 i2c_dev->adap.nr);
+		clk_i2c = NULL;
+	}
+
+	clk_parent = devm_clk_get(i2c_dev->dev, "source");
+	if (IS_ERR(clk_parent)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n",
+			 i2c_dev->adap.nr);
+		clk_parent = NULL;
+	}
+
+	if (clk_set_parent(clk_i2c, clk_parent))
+		i2c_dev->src_clk = clk_get_rate(clk_i2c);
+	else
+		i2c_dev->src_clk = 26000000;
+
+	dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n",
+		i2c_dev->adap.nr, i2c_dev->src_clk);
+
+	i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable");
+	if (IS_ERR(i2c_dev->clk)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the enable clock\n",
+			 i2c_dev->adap.nr);
+		i2c_dev->clk = NULL;
+	}
+
+	return 0;
+}
+
+static int sprd_i2c_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sprd_i2c *i2c_dev;
+	struct resource *res;
+	u32 prop;
+	int ret;
+
+	pdev->id = of_alias_get_id(dev->of_node, "i2c");
+
+	i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL);
+	if (!i2c_dev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	i2c_dev->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(i2c_dev->base))
+		return PTR_ERR(i2c_dev->base);
+
+	i2c_dev->irq = platform_get_irq(pdev, 0);
+	if (i2c_dev->irq < 0) {
+		dev_err(&pdev->dev, "failed to get irq resource\n");
+		return i2c_dev->irq;
+	}
+
+	i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
+	init_completion(&i2c_dev->complete);
+	snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
+		 "%s", "sprd-i2c");
+
+	i2c_dev->bus_freq = 100000;
+	i2c_dev->adap.owner = THIS_MODULE;
+	i2c_dev->dev = dev;
+	i2c_dev->adap.retries = 3;
+	i2c_dev->adap.algo = &sprd_i2c_algo;
+	i2c_dev->adap.algo_data = i2c_dev;
+	i2c_dev->adap.dev.parent = dev;
+	i2c_dev->adap.nr = pdev->id;
+	i2c_dev->adap.dev.of_node = dev->of_node;
+
+	if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop))
+		i2c_dev->bus_freq = prop;
+
+	/* We only support 100k and 400k now, otherwise will return error. */
+	if (i2c_dev->bus_freq != 100000 && i2c_dev->bus_freq != 400000)
+		return -EINVAL;
+
+	sprd_i2c_clk_init(i2c_dev);
+	platform_set_drvdata(pdev, i2c_dev);
+
+	ret = clk_prepare_enable(i2c_dev->clk);
+	if (ret)
+		return ret;
+
+	sprd_i2c_enable(i2c_dev);
+
+	pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(i2c_dev->dev);
+	pm_runtime_set_active(i2c_dev->dev);
+	pm_runtime_enable(i2c_dev->dev);
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "i2c%d pm runtime resume failed!\n",
+			pdev->id);
+		goto err_rpm_put;
+	}
+
+	ret = devm_request_threaded_irq(dev, i2c_dev->irq,
+		sprd_i2c_isr, sprd_i2c_isr_thread,
+		IRQF_NO_SUSPEND | IRQF_ONESHOT,
+		pdev->name, i2c_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq);
+		goto err_rpm_put;
+	}
+
+	ret = i2c_add_numbered_adapter(&i2c_dev->adap);
+	if (ret) {
+		dev_err(&pdev->dev, "add adapter failed\n");
+		goto err_rpm_put;
+	}
+
+	pm_runtime_mark_last_busy(i2c_dev->dev);
+	pm_runtime_put_autosuspend(i2c_dev->dev);
+	return 0;
+
+err_rpm_put:
+	pm_runtime_put_noidle(i2c_dev->dev);
+	pm_runtime_disable(i2c_dev->dev);
+	clk_disable_unprepare(i2c_dev->clk);
+	return ret;
+}
+
+static int sprd_i2c_remove(struct platform_device *pdev)
+{
+	struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0)
+		return ret;
+
+	i2c_del_adapter(&i2c_dev->adap);
+	clk_disable_unprepare(i2c_dev->clk);
+
+	pm_runtime_put_noidle(i2c_dev->dev);
+	pm_runtime_disable(i2c_dev->dev);
+
+	return 0;
+}
+
+static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev)
+{
+	return pm_runtime_force_suspend(pdev);
+}
+
+static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev)
+{
+	return pm_runtime_force_resume(pdev);
+}
+
+static int __maybe_unused sprd_i2c_runtime_suspend(struct device *pdev)
+{
+	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
+
+	clk_disable_unprepare(i2c_dev->clk);
+
+	return 0;
+}
+
+static int __maybe_unused sprd_i2c_runtime_resume(struct device *pdev)
+{
+	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
+	int ret;
+
+	ret = clk_prepare_enable(i2c_dev->clk);
+	if (ret)
+		return ret;
+
+	sprd_i2c_enable(i2c_dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops sprd_i2c_pm_ops = {
+	SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend,
+			   sprd_i2c_runtime_resume, NULL)
+
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq,
+				      sprd_i2c_resume_noirq)
+};
+
+static const struct of_device_id sprd_i2c_of_match[] = {
+	{ .compatible = "sprd,sc9860-i2c", },
+};
+
+static struct platform_driver sprd_i2c_driver = {
+	.probe = sprd_i2c_probe,
+	.remove = sprd_i2c_remove,
+	.driver = {
+		   .name = "sprd-i2c",
+		   .of_match_table = sprd_i2c_of_match,
+		   .pm = &sprd_i2c_pm_ops,
+	},
+};
+
+static int sprd_i2c_init(void)
+{
+	return platform_driver_register(&sprd_i2c_driver);
+}
+arch_initcall_sync(sprd_i2c_init);
-- 
1.7.9.5

[PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

This patch adds the I2C controller driver for Spreadtrum SC9860 platform.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
---
Changes since v2:
 - Remove some redundant comments and parens.
 - Define macros instead of magic number.
 - Add some comments to explain clock formula.
 - Change of_clk_get_by_name() to devm_clk_get().
 - Deal with other frequency.
 - Change register definiton to low case.
 - Change is_last_msg to boolean.
 - Other optimization.

Changes sice v1:
 - Power on I2C device in probe().
 - Remove redundant macros and usb __maybe_unused.
 - Remove redundant 'of_match_ptr'.
 - Modify return values and check the return value for 'clk_prepare_enable'.
---
 drivers/i2c/busses/Kconfig    |    7 +
 drivers/i2c/busses/Makefile   |    1 +
 drivers/i2c/busses/i2c-sprd.c |  683 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 691 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-sprd.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 8adc0f1..86476b9 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -877,6 +877,13 @@ config I2C_SIRF
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-sirf.
 
+config I2C_SPRD
+	bool "Spreadtrum I2C interface"
+	depends on ARCH_SPRD
+	help
+	  If you say yes to this option, support will be included for the
+	  Spreadtrum I2C interface.
+
 config I2C_ST
 	tristate "STMicroelectronics SSC I2C support"
 	depends on ARCH_STI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 30b6085..dd46c21 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
 obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
+obj-$(CONFIG_I2C_SPRD)		+= i2c-sprd.o
 obj-$(CONFIG_I2C_ST)		+= i2c-st.o
 obj-$(CONFIG_I2C_STM32F4)	+= i2c-stm32f4.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
new file mode 100644
index 0000000..a070f61
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sprd.c
@@ -0,0 +1,683 @@
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#define I2C_CTL			0x00
+#define I2C_ADDR_CFG		0x04
+#define I2C_COUNT		0x08
+#define I2C_RX			0x0c
+#define I2C_TX			0x10
+#define I2C_STATUS		0x14
+#define I2C_HSMODE_CFG		0x18
+#define I2C_VERSION		0x1c
+#define ADDR_DVD0		0x20
+#define ADDR_DVD1		0x24
+#define ADDR_STA0_DVD		0x28
+#define ADDR_RST		0x2c
+
+/* I2C_CTL */
+#define STP_EN			BIT(20)
+#define FIFO_AF_LVL_MASK	GENMASK(19, 16)
+#define FIFO_AF_LVL		16
+#define FIFO_AE_LVL_MASK	GENMASK(15, 12)
+#define FIFO_AE_LVL		12
+#define I2C_DMA_EN		BIT(11)
+#define FULL_INTEN		BIT(10)
+#define EMPTY_INTEN		BIT(9)
+#define I2C_DVD_OPT		BIT(8)
+#define I2C_OUT_OPT		BIT(7)
+#define I2C_TRIM_OPT		BIT(6)
+#define I2C_HS_MODE		BIT(4)
+#define I2C_MODE		BIT(3)
+#define I2C_EN			BIT(2)
+#define I2C_INT_EN		BIT(1)
+#define I2C_START		BIT(0)
+
+/* I2C_STATUS */
+#define SDA_IN			BIT(21)
+#define SCL_IN			BIT(20)
+#define FIFO_FULL		BIT(4)
+#define FIFO_EMPTY		BIT(3)
+#define I2C_INT			BIT(2)
+#define I2C_RX_ACK		BIT(1)
+#define I2C_BUSY		BIT(0)
+
+/* ADDR_RST */
+#define I2C_RST			BIT(0)
+
+#define I2C_FIFO_DEEP		12
+#define I2C_FIFO_FULL_THLD	15
+#define I2C_FIFO_EMPTY_THLD	4
+#define I2C_DATA_STEP		8
+#define I2C_ADDR_DVD0_CALC(high, low)	\
+	((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0)))
+#define I2C_ADDR_DVD1_CALC(high, low)	\
+	(((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16))
+
+/* timeout (ms) for pm runtime autosuspend */
+#define SPRD_I2C_PM_TIMEOUT	1000
+
+/* SPRD i2c data structure */
+struct sprd_i2c {
+	struct i2c_adapter adap;
+	struct device *dev;
+	void __iomem *base;
+	struct i2c_msg *msg;
+	struct clk *clk;
+	unsigned int src_clk;
+	unsigned int bus_freq;
+	struct completion complete;
+	u8 *buf;
+	u16 count;
+	int irq;
+	int err;
+};
+
+static void sprd_i2c_dump_reg(struct sprd_i2c *i2c_dev)
+{
+	dev_err(&i2c_dev->adap.dev, ": ======dump i2c-%d reg=======\n",
+		i2c_dev->adap.nr);
+	dev_err(&i2c_dev->adap.dev, ": I2C_CTRL:0x%x\n",
+		readl(i2c_dev->base + I2C_CTL));
+	dev_err(&i2c_dev->adap.dev, ": I2C_ADDR_CFG:0x%x\n",
+		readl(i2c_dev->base + I2C_ADDR_CFG));
+	dev_err(&i2c_dev->adap.dev, ": I2C_COUNT:0x%x\n",
+		readl(i2c_dev->base + I2C_COUNT));
+	dev_err(&i2c_dev->adap.dev, ": I2C_RX:0x%x\n",
+		readl(i2c_dev->base + I2C_RX));
+	dev_err(&i2c_dev->adap.dev, ": I2C_STATUS:0x%x\n",
+		readl(i2c_dev->base + I2C_STATUS));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_DVD0:0x%x\n",
+		readl(i2c_dev->base + ADDR_DVD0));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_DVD1:0x%x\n",
+		readl(i2c_dev->base + ADDR_DVD1));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_STA0_DVD:0x%x\n",
+		readl(i2c_dev->base + ADDR_STA0_DVD));
+	dev_err(&i2c_dev->adap.dev, ": ADDR_RST:0x%x\n",
+		readl(i2c_dev->base + ADDR_RST));
+}
+
+static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
+{
+	writel(count, i2c_dev->base + I2C_COUNT);
+}
+
+static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (stop)
+		writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL);
+	else
+		writel(tmp | STP_EN, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_STATUS);
+
+	writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS);
+}
+
+static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_STATUS);
+
+	writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS);
+}
+
+static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev)
+{
+	writel(I2C_RST, i2c_dev->base + ADDR_RST);
+}
+
+static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m)
+{
+	writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG);
+}
+
+static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
+{
+	u32 i;
+
+	for (i = 0; i < len; i++)
+		writeb(buf[i], i2c_dev->base + I2C_TX);
+}
+
+static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u16 len)
+{
+	u32 i;
+
+	for (i = 0; i < len; i++)
+		buf[i] = readb(i2c_dev->base + I2C_RX);
+}
+
+static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	tmp &= ~FIFO_AF_LVL_MASK;
+	tmp |= full_thld << FIFO_AF_LVL;
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	tmp &= ~FIFO_AE_LVL_MASK;
+	tmp |= empty_thld << FIFO_AE_LVL;
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (enable)
+		tmp |= FULL_INTEN;
+	else
+		tmp &= ~FULL_INTEN;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	if (enable)
+		tmp |= EMPTY_INTEN;
+	else
+		tmp &= ~EMPTY_INTEN;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+};
+
+static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = readl(i2c_dev->base + I2C_CTL);
+
+	writel(tmp | I2C_START, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw)
+{
+	unsigned int cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE;
+
+	writel(cmd | rw << 3, i2c_dev->base + I2C_CTL);
+}
+
+static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev)
+{
+	u32 i2c_count = i2c_dev->count;
+	u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP;
+	struct i2c_msg *msg = i2c_dev->msg;
+
+	if (msg->flags & I2C_M_RD) {
+		sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD);
+		i2c_dev->count -= I2C_FIFO_FULL_THLD;
+		i2c_dev->buf += I2C_FIFO_FULL_THLD;
+
+		/*
+		 * If the read data count is larger than rx fifo full threshold,
+		 * we should enable the rx fifo full interrupt to read data
+		 * again.
+		 */
+		if (i2c_dev->count >= I2C_FIFO_FULL_THLD)
+			sprd_i2c_set_fifo_full_int(i2c_dev, 1);
+	} else {
+		sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran);
+		i2c_dev->buf += need_tran;
+		i2c_dev->count -= need_tran;
+
+		/*
+		 * If the write data count is arger than tx fifo depth which
+		 * means we can not write all data in one time, then we should
+		 * enable the tx fifo empty interrupt to write again.
+		 */
+		if (i2c_count > I2C_FIFO_DEEP)
+			sprd_i2c_set_fifo_empty_int(i2c_dev, 1);
+	}
+}
+
+static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
+			       struct i2c_msg *msg, bool is_last_msg)
+{
+	struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
+
+	i2c_dev->msg = msg;
+	i2c_dev->buf = msg->buf;
+	i2c_dev->count = msg->len;
+
+	reinit_completion(&i2c_dev->complete);
+	sprd_i2c_reset_fifo(i2c_dev);
+	sprd_i2c_set_devaddr(i2c_dev, msg);
+	sprd_i2c_set_count(i2c_dev, msg->len);
+
+	if ((msg->flags & I2C_M_RD)) {
+		sprd_i2c_opt_mode(i2c_dev, 1);
+		sprd_i2c_send_stop(i2c_dev, 1);
+	} else {
+		sprd_i2c_opt_mode(i2c_dev, 0);
+		sprd_i2c_send_stop(i2c_dev, !!is_last_msg);
+	}
+
+	/*
+	 * We should enable rx fifo full interrupt to get data when receiving
+	 * full data.
+	 */
+	if ((msg->flags & I2C_M_RD))
+		sprd_i2c_set_fifo_full_int(i2c_dev, 1);
+	else
+		sprd_i2c_data_transfer(i2c_dev);
+
+	sprd_i2c_opt_start(i2c_dev);
+
+	wait_for_completion(&i2c_dev->complete);
+
+	return i2c_dev->err;
+}
+
+static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
+				struct i2c_msg *msgs, int num)
+{
+	struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
+	int im, ret;
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0)
+		return ret;
+
+	for (im = 0; im < num - 1; im++) {
+		ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
+		if (ret)
+			goto err_msg;
+	}
+
+	ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1);
+
+err_msg:
+	pm_runtime_mark_last_busy(i2c_dev->dev);
+	pm_runtime_put_autosuspend(i2c_dev->dev);
+
+	return ret < 0 ? ret : im;
+}
+
+static u32 sprd_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm sprd_i2c_algo = {
+	.master_xfer = sprd_i2c_master_xfer,
+	.functionality = sprd_i2c_func,
+};
+
+static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, unsigned int freq)
+{
+	u32 apb_clk = i2c_dev->src_clk;
+	/*
+	 * From I2C databook, the prescale calculation formula:
+	 * prescale = freq_i2c / (4 * freq_scl) - 1;
+	 */
+	u32 i2c_dvd = apb_clk / (4 * freq) - 1;
+	/*
+	 * From I2C databook, the high period of SCL clock is recommended as
+	 * 40% (2/5), and the low period of SCL clock is recommended as 60%
+	 * (3/5), then the formula should be:
+	 * high = (prescale * 2 * 2) / 5
+	 * low = (prescale * 2 * 3) / 5
+	 */
+	u32 high = ((i2c_dvd << 1) * 2) / 5;
+	u32 low = ((i2c_dvd << 1) * 3) / 5;
+	u32 div0 = I2C_ADDR_DVD0_CALC(high, low);
+	u32 div1 = I2C_ADDR_DVD1_CALC(high, low);
+
+	writel(div0, i2c_dev->base + ADDR_DVD0);
+	writel(div1, i2c_dev->base + ADDR_DVD1);
+
+	/* Start hold timing = hold time(us) * source clock */
+	if (freq == 400000)
+		writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD);
+	else if (freq == 100000)
+		writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD);
+}
+
+static void sprd_i2c_enable(struct sprd_i2c *i2c_dev)
+{
+	unsigned int tmp = I2C_DVD_OPT;
+
+	writel(tmp, i2c_dev->base + I2C_CTL);
+
+	sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD);
+	sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD);
+
+	sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq);
+	sprd_i2c_reset_fifo(i2c_dev);
+	sprd_i2c_clear_irq(i2c_dev);
+
+	tmp = readl(i2c_dev->base + I2C_CTL);
+	writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL);
+}
+
+static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id)
+{
+	struct sprd_i2c *i2c_dev = dev_id;
+	struct i2c_msg *msg = i2c_dev->msg;
+	int ack = readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK;
+	u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
+	u32 i2c_tran;
+
+	if (msg->flags & I2C_M_RD)
+		i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
+	else
+		i2c_tran = i2c_count;
+
+	/*
+	 * If we got one ACK from slave when writing data, and we did not
+	 * finish this transmission (i2c_tran is not zero), then we should
+	 * continue to write data.
+	 *
+	 * For reading data, ack is always 0, if i2c_tran is not 0 which
+	 * means we still need to contine to read data from slave.
+	 */
+	if (i2c_tran && !ack) {
+		sprd_i2c_data_transfer(i2c_dev);
+		return IRQ_HANDLED;
+	}
+
+	i2c_dev->err = 0;
+
+	/*
+	 * If we did not get one ACK from slave when writing data, we should
+	 * dump all registers to check I2C status.
+	 */
+	if (ack) {
+		i2c_dev->err = -EIO;
+		sprd_i2c_dump_reg(i2c_dev);
+	} else if (msg->flags & I2C_M_RD && i2c_dev->count) {
+		sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count);
+	}
+
+	/* Transmission is done and clear ack and start operation */
+	sprd_i2c_clear_ack(i2c_dev);
+	sprd_i2c_clear_start(i2c_dev);
+	complete(&i2c_dev->complete);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t sprd_i2c_isr(int irq, void *dev_id)
+{
+	struct sprd_i2c *i2c_dev = dev_id;
+	struct i2c_msg *msg = i2c_dev->msg;
+	u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
+	int ack = readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK;
+	u32 i2c_tran;
+
+	if (msg->flags & I2C_M_RD)
+		i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
+	else
+		i2c_tran = i2c_count;
+
+	/*
+	 * If ack == 0 means we got one ACK, if ack != 0 means we did not
+	 * get one ACK from slave when writing data, then we should finish
+	 * this transmission since we got some errors.
+	 *
+	 * When writing data, if i2c_tran == 0 which means we have writen
+	 * done all data, then we can finish this transmission.
+	 *
+	 * When reading data, if conut < rx fifo full threshold, which
+	 * means we can read all data in one time, then we can finish this
+	 * transmission too.
+	 */
+	if (!i2c_tran || ack) {
+		sprd_i2c_clear_start(i2c_dev);
+		sprd_i2c_clear_irq(i2c_dev);
+	}
+
+	sprd_i2c_set_fifo_empty_int(i2c_dev, 0);
+	sprd_i2c_set_fifo_full_int(i2c_dev, 0);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev)
+{
+	struct clk *clk_i2c, *clk_parent;
+
+	clk_i2c = devm_clk_get(i2c_dev->dev, "i2c");
+	if (IS_ERR(clk_i2c)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n",
+			 i2c_dev->adap.nr);
+		clk_i2c = NULL;
+	}
+
+	clk_parent = devm_clk_get(i2c_dev->dev, "source");
+	if (IS_ERR(clk_parent)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n",
+			 i2c_dev->adap.nr);
+		clk_parent = NULL;
+	}
+
+	if (clk_set_parent(clk_i2c, clk_parent))
+		i2c_dev->src_clk = clk_get_rate(clk_i2c);
+	else
+		i2c_dev->src_clk = 26000000;
+
+	dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n",
+		i2c_dev->adap.nr, i2c_dev->src_clk);
+
+	i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable");
+	if (IS_ERR(i2c_dev->clk)) {
+		dev_warn(i2c_dev->dev, "i2c%d can't get the enable clock\n",
+			 i2c_dev->adap.nr);
+		i2c_dev->clk = NULL;
+	}
+
+	return 0;
+}
+
+static int sprd_i2c_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sprd_i2c *i2c_dev;
+	struct resource *res;
+	u32 prop;
+	int ret;
+
+	pdev->id = of_alias_get_id(dev->of_node, "i2c");
+
+	i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL);
+	if (!i2c_dev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	i2c_dev->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(i2c_dev->base))
+		return PTR_ERR(i2c_dev->base);
+
+	i2c_dev->irq = platform_get_irq(pdev, 0);
+	if (i2c_dev->irq < 0) {
+		dev_err(&pdev->dev, "failed to get irq resource\n");
+		return i2c_dev->irq;
+	}
+
+	i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
+	init_completion(&i2c_dev->complete);
+	snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
+		 "%s", "sprd-i2c");
+
+	i2c_dev->bus_freq = 100000;
+	i2c_dev->adap.owner = THIS_MODULE;
+	i2c_dev->dev = dev;
+	i2c_dev->adap.retries = 3;
+	i2c_dev->adap.algo = &sprd_i2c_algo;
+	i2c_dev->adap.algo_data = i2c_dev;
+	i2c_dev->adap.dev.parent = dev;
+	i2c_dev->adap.nr = pdev->id;
+	i2c_dev->adap.dev.of_node = dev->of_node;
+
+	if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop))
+		i2c_dev->bus_freq = prop;
+
+	/* We only support 100k and 400k now, otherwise will return error. */
+	if (i2c_dev->bus_freq != 100000 && i2c_dev->bus_freq != 400000)
+		return -EINVAL;
+
+	sprd_i2c_clk_init(i2c_dev);
+	platform_set_drvdata(pdev, i2c_dev);
+
+	ret = clk_prepare_enable(i2c_dev->clk);
+	if (ret)
+		return ret;
+
+	sprd_i2c_enable(i2c_dev);
+
+	pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(i2c_dev->dev);
+	pm_runtime_set_active(i2c_dev->dev);
+	pm_runtime_enable(i2c_dev->dev);
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "i2c%d pm runtime resume failed!\n",
+			pdev->id);
+		goto err_rpm_put;
+	}
+
+	ret = devm_request_threaded_irq(dev, i2c_dev->irq,
+		sprd_i2c_isr, sprd_i2c_isr_thread,
+		IRQF_NO_SUSPEND | IRQF_ONESHOT,
+		pdev->name, i2c_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq);
+		goto err_rpm_put;
+	}
+
+	ret = i2c_add_numbered_adapter(&i2c_dev->adap);
+	if (ret) {
+		dev_err(&pdev->dev, "add adapter failed\n");
+		goto err_rpm_put;
+	}
+
+	pm_runtime_mark_last_busy(i2c_dev->dev);
+	pm_runtime_put_autosuspend(i2c_dev->dev);
+	return 0;
+
+err_rpm_put:
+	pm_runtime_put_noidle(i2c_dev->dev);
+	pm_runtime_disable(i2c_dev->dev);
+	clk_disable_unprepare(i2c_dev->clk);
+	return ret;
+}
+
+static int sprd_i2c_remove(struct platform_device *pdev)
+{
+	struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0)
+		return ret;
+
+	i2c_del_adapter(&i2c_dev->adap);
+	clk_disable_unprepare(i2c_dev->clk);
+
+	pm_runtime_put_noidle(i2c_dev->dev);
+	pm_runtime_disable(i2c_dev->dev);
+
+	return 0;
+}
+
+static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev)
+{
+	return pm_runtime_force_suspend(pdev);
+}
+
+static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev)
+{
+	return pm_runtime_force_resume(pdev);
+}
+
+static int __maybe_unused sprd_i2c_runtime_suspend(struct device *pdev)
+{
+	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
+
+	clk_disable_unprepare(i2c_dev->clk);
+
+	return 0;
+}
+
+static int __maybe_unused sprd_i2c_runtime_resume(struct device *pdev)
+{
+	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
+	int ret;
+
+	ret = clk_prepare_enable(i2c_dev->clk);
+	if (ret)
+		return ret;
+
+	sprd_i2c_enable(i2c_dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops sprd_i2c_pm_ops = {
+	SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend,
+			   sprd_i2c_runtime_resume, NULL)
+
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq,
+				      sprd_i2c_resume_noirq)
+};
+
+static const struct of_device_id sprd_i2c_of_match[] = {
+	{ .compatible = "sprd,sc9860-i2c", },
+};
+
+static struct platform_driver sprd_i2c_driver = {
+	.probe = sprd_i2c_probe,
+	.remove = sprd_i2c_remove,
+	.driver = {
+		   .name = "sprd-i2c",
+		   .of_match_table = sprd_i2c_of_match,
+		   .pm = &sprd_i2c_pm_ops,
+	},
+};
+
+static int sprd_i2c_init(void)
+{
+	return platform_driver_register(&sprd_i2c_driver);
+}
+arch_initcall_sync(sprd_i2c_init);
-- 
1.7.9.5

Re: [PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

Hi Andy and Wolfram,

On 一,  6月 26, 2017 at 06:28:14下午 +0800, Baolin Wang wrote:
> This patch adds the I2C controller driver for Spreadtrum SC9860 platform.
> 
> Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
> ---
> Changes since v2:
>  - Remove some redundant comments and parens.
>  - Define macros instead of magic number.
>  - Add some comments to explain clock formula.
>  - Change of_clk_get_by_name() to devm_clk_get().
>  - Deal with other frequency.
>  - Change register definiton to low case.
>  - Change is_last_msg to boolean.
>  - Other optimization.
> 
> Changes sice v1:
>  - Power on I2C device in probe().
>  - Remove redundant macros and usb __maybe_unused.
>  - Remove redundant 'of_match_ptr'.
>  - Modify return values and check the return value for 'clk_prepare_enable'.
> ---

Do you have any more comments about this patch? Thanks.

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Re: [PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

Hi Andy and Wolfram,

On 一,  6月 26, 2017 at 06:28:14下午 +0800, Baolin Wang wrote:
> This patch adds the I2C controller driver for Spreadtrum SC9860 platform.
> 
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
> Changes since v2:
>  - Remove some redundant comments and parens.
>  - Define macros instead of magic number.
>  - Add some comments to explain clock formula.
>  - Change of_clk_get_by_name() to devm_clk_get().
>  - Deal with other frequency.
>  - Change register definiton to low case.
>  - Change is_last_msg to boolean.
>  - Other optimization.
> 
> Changes sice v1:
>  - Power on I2C device in probe().
>  - Remove redundant macros and usb __maybe_unused.
>  - Remove redundant 'of_match_ptr'.
>  - Modify return values and check the return value for 'clk_prepare_enable'.
> ---

Do you have any more comments about this patch? Thanks.

Re: [PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Chunyan Zhang]

Hi Baolin,

On 26 June 2017 at 18:28, Baolin Wang <baolin.wang@spreadtrum.com> wrote:
> This patch adds the I2C controller driver for Spreadtrum SC9860 platform.
>
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
> Changes since v2:
>  - Remove some redundant comments and parens.
>  - Define macros instead of magic number.
>  - Add some comments to explain clock formula.
>  - Change of_clk_get_by_name() to devm_clk_get().
>  - Deal with other frequency.
>  - Change register definiton to low case.
>  - Change is_last_msg to boolean.
>  - Other optimization.
>
> Changes sice v1:
>  - Power on I2C device in probe().
>  - Remove redundant macros and usb __maybe_unused.
>  - Remove redundant 'of_match_ptr'.
>  - Modify return values and check the return value for 'clk_prepare_enable'.
> ---
>  drivers/i2c/busses/Kconfig    |    7 +
>  drivers/i2c/busses/Makefile   |    1 +
>  drivers/i2c/busses/i2c-sprd.c |  683 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 691 insertions(+)
>  create mode 100644 drivers/i2c/busses/i2c-sprd.c
>

[snip]

> diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> new file mode 100644
> index 0000000..a070f61
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sprd.c
> @@ -0,0 +1,683 @@
> +/*
> + * Copyright (C) 2017 Spreadtrum Communications Inc.
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */

According to RobH's comments [1], we're switching to use
SPDX-License-Identifier tag instead, like [2].

[1] http://lkml.iu.edu/hypermail/linux/kernel/1702.2/05122.html
[2] http://elixir.free-electrons.com/linux/v4.12/source/arch/arm64/boot/dts/sprd/sp9860g-1h10.dts#L6


Thanks,
Chunyan

Re: [PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

Hi Chunyan,

On 一,  7月 03, 2017 at 05:29:57下午 +0800, Chunyan Zhang wrote:
> Hi Baolin,
> 
> On 26 June 2017 at 18:28, Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org> wrote:
> > This patch adds the I2C controller driver for Spreadtrum SC9860 platform.
> >
> > Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
> > ---
> > Changes since v2:
> >  - Remove some redundant comments and parens.
> >  - Define macros instead of magic number.
> >  - Add some comments to explain clock formula.
> >  - Change of_clk_get_by_name() to devm_clk_get().
> >  - Deal with other frequency.
> >  - Change register definiton to low case.
> >  - Change is_last_msg to boolean.
> >  - Other optimization.
> >
> > Changes sice v1:
> >  - Power on I2C device in probe().
> >  - Remove redundant macros and usb __maybe_unused.
> >  - Remove redundant 'of_match_ptr'.
> >  - Modify return values and check the return value for 'clk_prepare_enable'.
> > ---
> >  drivers/i2c/busses/Kconfig    |    7 +
> >  drivers/i2c/busses/Makefile   |    1 +
> >  drivers/i2c/busses/i2c-sprd.c |  683 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 691 insertions(+)
> >  create mode 100644 drivers/i2c/busses/i2c-sprd.c
> >
> 
> [snip]
> 
> > diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> > new file mode 100644
> > index 0000000..a070f61
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-sprd.c
> > @@ -0,0 +1,683 @@
> > +/*
> > + * Copyright (C) 2017 Spreadtrum Communications Inc.
> > + *
> > + * This software is licensed under the terms of the GNU General Public
> > + * License version 2, as published by the Free Software Foundation, and
> > + * may be copied, distributed, and modified under those terms.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> 
> According to RobH's comments [1], we're switching to use
> SPDX-License-Identifier tag instead, like [2].
> 
> [1] http://lkml.iu.edu/hypermail/linux/kernel/1702.2/05122.html
> [2] http://elixir.free-electrons.com/linux/v4.12/source/arch/arm64/boot/dts/sprd/sp9860g-1h10.dts#L6

Will use SPDX-License-Identifier tag instead and resend. Thanks.

> 
> Thanks,
> Chunyan
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Re: [PATCH v3 2/2] i2c: Add Spreadtrum I2C controller driver

[Baolin Wang]

Hi Chunyan,

On 一,  7月 03, 2017 at 05:29:57下午 +0800, Chunyan Zhang wrote:
> Hi Baolin,
> 
> On 26 June 2017 at 18:28, Baolin Wang <baolin.wang@spreadtrum.com> wrote:
> > This patch adds the I2C controller driver for Spreadtrum SC9860 platform.
> >
> > Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> > ---
> > Changes since v2:
> >  - Remove some redundant comments and parens.
> >  - Define macros instead of magic number.
> >  - Add some comments to explain clock formula.
> >  - Change of_clk_get_by_name() to devm_clk_get().
> >  - Deal with other frequency.
> >  - Change register definiton to low case.
> >  - Change is_last_msg to boolean.
> >  - Other optimization.
> >
> > Changes sice v1:
> >  - Power on I2C device in probe().
> >  - Remove redundant macros and usb __maybe_unused.
> >  - Remove redundant 'of_match_ptr'.
> >  - Modify return values and check the return value for 'clk_prepare_enable'.
> > ---
> >  drivers/i2c/busses/Kconfig    |    7 +
> >  drivers/i2c/busses/Makefile   |    1 +
> >  drivers/i2c/busses/i2c-sprd.c |  683 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 691 insertions(+)
> >  create mode 100644 drivers/i2c/busses/i2c-sprd.c
> >
> 
> [snip]
> 
> > diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> > new file mode 100644
> > index 0000000..a070f61
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-sprd.c
> > @@ -0,0 +1,683 @@
> > +/*
> > + * Copyright (C) 2017 Spreadtrum Communications Inc.
> > + *
> > + * This software is licensed under the terms of the GNU General Public
> > + * License version 2, as published by the Free Software Foundation, and
> > + * may be copied, distributed, and modified under those terms.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> 
> According to RobH's comments [1], we're switching to use
> SPDX-License-Identifier tag instead, like [2].
> 
> [1] http://lkml.iu.edu/hypermail/linux/kernel/1702.2/05122.html
> [2] http://elixir.free-electrons.com/linux/v4.12/source/arch/arm64/boot/dts/sprd/sp9860g-1h10.dts#L6

Will use SPDX-License-Identifier tag instead and resend. Thanks.

> 
> Thanks,
> Chunyan

Re: [PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Rob Herring]

On Mon, Jun 26, 2017 at 5:28 AM, Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org> wrote:
> This patch adds the binding documentation for Spreadtrum I2C
> controller device.
>
> Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
> ---
> Changes since v2:
>  - Change compatible strings to be SoC specific.
>
> Changes since v1:
>  - No updates.
> ---
>  Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
>  1 file changed, 31 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt

Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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Re: [PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Rob Herring]

On Mon, Jun 26, 2017 at 5:28 AM, Baolin Wang <baolin.wang@spreadtrum.com> wrote:
> This patch adds the binding documentation for Spreadtrum I2C
> controller device.
>
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
> Changes since v2:
>  - Change compatible strings to be SoC specific.
>
> Changes since v1:
>  - No updates.
> ---
>  Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
>  1 file changed, 31 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Baolin Wang]

On 一,  6月 26, 2017 at 09:05:39上午 -0500, Rob Herring wrote:
> On Mon, Jun 26, 2017 at 5:28 AM, Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org> wrote:
> > This patch adds the binding documentation for Spreadtrum I2C
> > controller device.
> >
> > Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
> > ---
> > Changes since v2:
> >  - Change compatible strings to be SoC specific.
> >
> > Changes since v1:
> >  - No updates.
> > ---
> >  Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
> >  1 file changed, 31 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt
> 
> Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Thanks Rob.

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Re: [PATCH v3 1/2] dt-bindings: i2c: Add Spreadtrum I2C controller documentation

[Baolin Wang]

On 一,  6月 26, 2017 at 09:05:39上午 -0500, Rob Herring wrote:
> On Mon, Jun 26, 2017 at 5:28 AM, Baolin Wang <baolin.wang@spreadtrum.com> wrote:
> > This patch adds the binding documentation for Spreadtrum I2C
> > controller device.
> >
> > Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> > ---
> > Changes since v2:
> >  - Change compatible strings to be SoC specific.
> >
> > Changes since v1:
> >  - No updates.
> > ---
> >  Documentation/devicetree/bindings/i2c/i2c-sprd.txt |   31 ++++++++++++++++++++
> >  1 file changed, 31 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sprd.txt
> 
> Acked-by: Rob Herring <robh@kernel.org>

Thanks Rob.