[PATCH v4] clk/axs10x: Add I2S PLL clock driver

Jose Abreu
2016-04-04T18:00:57Z

The ARC SDP I2S clock can be programmed using a
specific PLL.

This patch has the goal of adding a clock driver
that programs this PLL.

At this moment the rate values are hardcoded in
a table but in the future it would be ideal to
use a function which determines the PLL values
given the desired rate.

Signed-off-by: Jose Abreu <joabreu at synopsys.com>
---

Changes v3 -> v4:
* Added binding document (as suggested by Stephen Boyd)
* Minor code style fixes (as suggested by Stephen Boyd)
* Use ioremap (as suggested by Stephen Boyd)
* Implement round_rate (as suggested by Stephen Boyd)
* Change to platform driver (as suggested by Stephen Boyd)
* Use {readl/writel}_relaxed (as suggested by Vineet Gupta)

Changes v2 -> v3:
* Implemented recalc_rate

Changes v1 -> v2:
* Renamed folder to axs10x (as suggested by Alexey Brodkin)
* Added more supported rates

.../devicetree/bindings/clock/i2s-pll-clock.txt | 17 ++
drivers/clk/Makefile | 1 +
drivers/clk/axs10x/Makefile | 1 +
drivers/clk/axs10x/i2s_pll_clock.c | 217 +++++++++++++++++++++
4 files changed, 236 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/i2s-pll-clock.txt
create mode 100644 drivers/clk/axs10x/Makefile
create mode 100644 drivers/clk/axs10x/i2s_pll_clock.c

diff --git a/Documentation/devicetree/bindings/clock/i2s-pll-clock.txt b/Documentation/devicetree/bindings/clock/i2s-pll-clock.txt
new file mode 100644
index 0000000..ff86a41
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/i2s-pll-clock.txt
@@ -0,0 +1,17 @@
+Binding for the AXS10X I2S PLL clock
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible: shall be "snps,i2s-pll-clock"
+- #clock-cells: from common clock binding; Should always be set to 0.
+- reg : Address and length of the I2S PLL register set.
+
+Example:
+ clock at 0x100a0 {
+ compatible = "snps,i2s-pll-clock";
+ reg = <0x100a0 0x10>;
+ #clock-cells = <0>;
+ };
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 46869d6..2ca62dc6 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -84,3 +84,4 @@ obj-$(CONFIG_X86) += x86/
obj-$(CONFIG_ARCH_ZX) += zte/
obj-$(CONFIG_ARCH_ZYNQ) += zynq/
obj-$(CONFIG_H8300) += h8300/
+obj-$(CONFIG_ARC_PLAT_AXS10X) += axs10x/
diff --git a/drivers/clk/axs10x/Makefile b/drivers/clk/axs10x/Makefile
new file mode 100644
index 0000000..01996b8
--- /dev/null
+++ b/drivers/clk/axs10x/Makefile
@@ -0,0 +1 @@
+obj-y += i2s_pll_clock.o
diff --git a/drivers/clk/axs10x/i2s_pll_clock.c b/drivers/clk/axs10x/i2s_pll_clock.c
new file mode 100644
index 0000000..3ba4e2f
--- /dev/null
+++ b/drivers/clk/axs10x/i2s_pll_clock.c
@@ -0,0 +1,217 @@
+/*
+ * Synopsys AXS10X SDP I2S PLL clock driver
+ *
+ * Copyright (C) 2016 Synopsys
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+/* FPGA Version Info */
+#define FPGA_VER_INFO 0xE0011230
+#define FPGA_VER_27M 0x000FBED9
+
+/* PLL registers addresses */
+#define PLL_IDIV_REG 0x0
+#define PLL_FBDIV_REG 0x4
+#define PLL_ODIV0_REG 0x8
+#define PLL_ODIV1_REG 0xC
+
+struct i2s_pll_cfg {
+ unsigned int rate;
+ unsigned int idiv;
+ unsigned int fbdiv;
+ unsigned int odiv0;
+ unsigned int odiv1;
+};
+
+static const struct i2s_pll_cfg i2s_pll_cfg_27m[] = {
+ /* 27 Mhz */
+ { 1024000, 0x104, 0x451, 0x10E38, 0x2000 },
+ { 1411200, 0x104, 0x596, 0x10D35, 0x2000 },
+ { 1536000, 0x208, 0xA28, 0x10B2C, 0x2000 },
+ { 2048000, 0x82, 0x451, 0x10E38, 0x2000 },
+ { 2822400, 0x82, 0x596, 0x10D35, 0x2000 },
+ { 3072000, 0x104, 0xA28, 0x10B2C, 0x2000 },
+ { 2116800, 0x82, 0x3CF, 0x10C30, 0x2000 },
+ { 2304000, 0x104, 0x79E, 0x10B2C, 0x2000 },
+ { 0, 0, 0, 0, 0 },
+};
+
+static const struct i2s_pll_cfg i2s_pll_cfg_28m[] = {
+ /* 28.224 Mhz */
+ { 1024000, 0x82, 0x105, 0x107DF, 0x2000 },
+ { 1411200, 0x28A, 0x1, 0x10001, 0x2000 },
+ { 1536000, 0xA28, 0x187, 0x10042, 0x2000 },
+ { 2048000, 0x41, 0x105, 0x107DF, 0x2000 },
+ { 2822400, 0x145, 0x1, 0x10001, 0x2000 },
+ { 3072000, 0x514, 0x187, 0x10042, 0x2000 },
+ { 2116800, 0x514, 0x42, 0x10001, 0x2000 },
+ { 2304000, 0x619, 0x82, 0x10001, 0x2000 },
+ { 0, 0, 0, 0, 0 },
+};
+
+struct i2s_pll_clk {
+ void __iomem *base;
+ struct clk_hw hw;
+ unsigned int ref_clk;
+ const struct i2s_pll_cfg *pll_cfg;
+};
+
+static inline void i2s_pll_write(struct i2s_pll_clk *clk, unsigned int reg,
+ unsigned int val)
+{
+ writel_relaxed(val, clk->base + reg);
+}
+
+static inline unsigned int i2s_pll_read(struct i2s_pll_clk *clk,
+ unsigned int reg)
+{
+ return readl_relaxed(clk->base + reg);
+}
+
+static inline struct i2s_pll_clk *to_i2s_pll_clk(struct clk_hw *hw)
+{
+ return container_of(hw, struct i2s_pll_clk, hw);
+}
+
+static unsigned int i2s_pll_get_value(unsigned int val)
+{
+ return (val & 0x3F) + ((val >> 6) & 0x3F);
+}
+
+static unsigned long i2s_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
+ unsigned int idiv, fbdiv, odiv;
+
+ idiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_IDIV_REG));
+ fbdiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_FBDIV_REG));
+ odiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_ODIV0_REG));
+
+ return ((clk->ref_clk / idiv) * fbdiv) / odiv;
+}
+
+static long i2s_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ const struct i2s_pll_cfg *pll_cfg = to_i2s_pll_clk(hw)->pll_cfg;
+ int i;
+
+ for (i = 0; pll_cfg[i].rate != 0; i++)
+ if (pll_cfg[i].rate == rate)
+ return rate;
+
+ return -EINVAL;
+}
+
+static int i2s_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
+ const struct i2s_pll_cfg *pll_cfg = clk->pll_cfg;
+ int i;
+
+ for (i = 0; pll_cfg[i].rate != 0; i++) {
+ if (pll_cfg[i].rate == rate) {
+ i2s_pll_write(clk, PLL_IDIV_REG, pll_cfg[i].idiv);
+ i2s_pll_write(clk, PLL_FBDIV_REG, pll_cfg[i].fbdiv);
+ i2s_pll_write(clk, PLL_ODIV0_REG, pll_cfg[i].odiv0);
+ i2s_pll_write(clk, PLL_ODIV1_REG, pll_cfg[i].odiv1);
+ return 0;
+ }
+ }
+
+ pr_err("%s: invalid rate=%ld, parent_rate=%ld\n", __func__,
+ rate, parent_rate);
+ return -EINVAL;
+}
+
+static const struct clk_ops i2s_pll_ops = {
+ .recalc_rate = i2s_pll_recalc_rate,
+ .round_rate = i2s_pll_round_rate,
+ .set_rate = i2s_pll_set_rate,
+};
+
+static int i2s_pll_clk_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
+ const char *clk_name;
+ struct clk *clk;
+ struct i2s_pll_clk *pll_clk;
+ struct clk_init_data init;
+ struct resource *mem;
+
+ if (!node)
+ return -ENODEV;
+
+ pll_clk = devm_kzalloc(dev, sizeof(*pll_clk), GFP_KERNEL);
+ if (!pll_clk)
+ return -ENOMEM;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pll_clk->base = devm_ioremap_resource(dev, mem);
+ if (IS_ERR(pll_clk->base))
+ return PTR_ERR(pll_clk->base);
+
+ clk_name = node->name;
+ init.name = clk_name;
+ init.ops = &i2s_pll_ops;
+ init.num_parents = 0;
+ pll_clk->hw.init = &init;
+
+ clk = clk_register(NULL, &pll_clk->hw);
+ if (IS_ERR(clk)) {
+ dev_err(dev, "failed to register %s div clock (%ld)\n",
+ clk_name, PTR_ERR(clk));
+ return PTR_ERR(clk);
+ }
+
+ if (readl((void *)FPGA_VER_INFO) <= FPGA_VER_27M) {
+ pll_clk->ref_clk = 27000000;
+ pll_clk->pll_cfg = i2s_pll_cfg_27m;
+ } else {
+ pll_clk->ref_clk = 28224000;
+ pll_clk->pll_cfg = i2s_pll_cfg_28m;
+ }
+
+ return of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+
+static int i2s_pll_clk_remove(struct platform_device *pdev)
+{
+ of_clk_del_provider(pdev->dev.of_node);
+ return 0;
+}
+
+static const struct of_device_id i2s_pll_clk_id[] = {
+ { .compatible = "snps,i2s-pll-clock", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, i2s_pll_clk_id);
+
+static struct platform_driver i2s_pll_clk_driver = {
+ .driver = {
+ .name = "i2s-pll-clock",
+ .of_match_table = of_match_ptr(i2s_pll_clk_id),
+ },
+ .probe = i2s_pll_clk_probe,
+ .remove = i2s_pll_clk_remove,
+};
+module_platform_driver(i2s_pll_clk_driver);
+
+MODULE_AUTHOR("Jose Abreu <joabreu at synopsys.com>");
+MODULE_DESCRIPTION("Synopsys AXS10X SDP I2S PLL Clock Driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1