From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Subject: [PATCH v3] i2c: new bus driver for efm32 Date: Fri, 21 Mar 2014 16:03:56 +0100 Message-ID: <1395414236-22647-1-git-send-email-u.kleine-koenig@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Wolfram Sang Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org This was tested on a EFM32GG-DK3750 devboard that has a temperature sensor and an eeprom on its i2c bus. Signed-off-by: Uwe Kleine-K=C3=B6nig --- Notes: Changes since (implicit) v1, sent with Message-Id: 1392027598-29015= -1-git-send-email-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org - drop non-dt support - drop locking - don't only use -EIO on error - drop many dev_dbg - use reinit_completion instead of (repeated) init_completion - fix .remove callback to also remove the i2c adapter - use -EINVAL for clock problems - use namespace for location property - don't BUG but reset hardware on unexpected failure - add dt binding doc =20 Changes since v2, sent with Message-Id: 1395349551-27047-1-git-send= -email-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org - make it actually compile :-| .../devicetree/bindings/i2c/i2c-efm32.txt | 34 ++ drivers/i2c/busses/Kconfig | 7 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-efm32.c | 482 +++++++++++++= ++++++++ 4 files changed, 524 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-efm32.txt create mode 100644 drivers/i2c/busses/i2c-efm32.c diff --git a/Documentation/devicetree/bindings/i2c/i2c-efm32.txt b/Docu= mentation/devicetree/bindings/i2c/i2c-efm32.txt new file mode 100644 index 000000000000..ead4dd33ab66 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-efm32.txt @@ -0,0 +1,34 @@ +* Energymicro efm32 i2c controller + +Required properties : + + - reg : Offset and length of the register set for the device + - compatible : should be "efm32,i2c" + - interrupts : the interrupt number + - clocks : reference to the module clock + +Recommended properties : + + - clock-frequency : maximal I2C bus clock frequency in Hz. + - efm32,location : Decides the location of the USART I/O pins. + Allowed range : [0 .. 6] + +Example: + i2c0: i2c@4000a000 { + #address-cells =3D <1>; + #size-cells =3D <0>; + compatible =3D "efm32,i2c"; + reg =3D <0x4000a000 0x400>; + interrupts =3D <9>; + clocks =3D <&cmu clk_HFPERCLKI2C0>; + clock-frequency =3D <100000>; + status =3D "disabled"; + efm32,location =3D <3>; + + eeprom@50 { + compatible =3D "microchip,24c02"; + reg =3D <0x50>; + pagesize =3D <16>; + }; + }; + diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index f5ed03164d86..7322ff0c4c60 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -432,6 +432,13 @@ config I2C_DESIGNWARE_PCI This driver can also be built as a module. If so, the module will be called i2c-designware-pci. =20 +config I2C_EFM32 + tristate "EFM32 I2C controller" + depends on OF && (ARCH_EFM32 || COMPILE_TEST) + help + This driver supports the i2c block found in Energy Micro's EFM32 + SoCs. + config I2C_EG20T tristate "Intel EG20T PCH/LAPIS Semicon IOH(ML7213/ML7223/ML7831) I2C= " depends on PCI diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index a08931fe73e1..2a56ab181851 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -41,6 +41,7 @@ obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM) +=3D i2c-design= ware-platform.o i2c-designware-platform-objs :=3D i2c-designware-platdrv.o obj-$(CONFIG_I2C_DESIGNWARE_PCI) +=3D i2c-designware-pci.o i2c-designware-pci-objs :=3D i2c-designware-pcidrv.o +obj-$(CONFIG_I2C_EFM32) +=3D i2c-efm32.o obj-$(CONFIG_I2C_EG20T) +=3D i2c-eg20t.o obj-$(CONFIG_I2C_EXYNOS5) +=3D i2c-exynos5.o obj-$(CONFIG_I2C_GPIO) +=3D i2c-gpio.o diff --git a/drivers/i2c/busses/i2c-efm32.c b/drivers/i2c/busses/i2c-ef= m32.c new file mode 100644 index 000000000000..bef8c2702516 --- /dev/null +++ b/drivers/i2c/busses/i2c-efm32.c @@ -0,0 +1,482 @@ +/* + * Copyright (C) 2014 Uwe Kleine-Koenig for Pengutronix + * + * This program is free software; you can redistribute it and/or modif= y it under + * the terms of the GNU General Public License version 2 as published = by the + * Free Software Foundation. + */ +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_NAME "efm32-i2c" + +#define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask) + +#define REG_CTRL 0x00 +#define REG_CTRL_EN 0x00001 +#define REG_CTRL_SLAVE 0x00002 +#define REG_CTRL_AUTOACK 0x00004 +#define REG_CTRL_AUTOSE 0x00008 +#define REG_CTRL_AUTOSN 0x00010 +#define REG_CTRL_ARBDIS 0x00020 +#define REG_CTRL_GCAMEN 0x00040 +#define REG_CTRL_CLHR__MASK 0x00300 +#define REG_CTRL_BITO__MASK 0x03000 +#define REG_CTRL_BITO_OFF 0x00000 +#define REG_CTRL_BITO_40PCC 0x01000 +#define REG_CTRL_BITO_80PCC 0x02000 +#define REG_CTRL_BITO_160PCC 0x03000 +#define REG_CTRL_GIBITO 0x08000 +#define REG_CTRL_CLTO__MASK 0x70000 +#define REG_CTRL_CLTO_OFF 0x00000 + +#define REG_CMD 0x04 +#define REG_CMD_START 0x00001 +#define REG_CMD_STOP 0x00002 +#define REG_CMD_ACK 0x00004 +#define REG_CMD_NACK 0x00008 +#define REG_CMD_CONT 0x00010 +#define REG_CMD_ABORT 0x00020 +#define REG_CMD_CLEARTX 0x00040 +#define REG_CMD_CLEARPC 0x00080 + +#define REG_STATE 0x08 +#define REG_STATE_BUSY 0x00001 +#define REG_STATE_MASTER 0x00002 +#define REG_STATE_TRANSMITTER 0x00004 +#define REG_STATE_NACKED 0x00008 +#define REG_STATE_BUSHOLD 0x00010 +#define REG_STATE_STATE__MASK 0x000e0 +#define REG_STATE_STATE_IDLE 0x00000 +#define REG_STATE_STATE_WAIT 0x00020 +#define REG_STATE_STATE_START 0x00040 +#define REG_STATE_STATE_ADDR 0x00060 +#define REG_STATE_STATE_ADDRACK 0x00080 +#define REG_STATE_STATE_DATA 0x000a0 +#define REG_STATE_STATE_DATAACK 0x000c0 + +#define REG_STATUS 0x0c +#define REG_STATUS_PSTART 0x00001 +#define REG_STATUS_PSTOP 0x00002 +#define REG_STATUS_PACK 0x00004 +#define REG_STATUS_PNACK 0x00008 +#define REG_STATUS_PCONT 0x00010 +#define REG_STATUS_PABORT 0x00020 +#define REG_STATUS_TXC 0x00040 +#define REG_STATUS_TXBL 0x00080 +#define REG_STATUS_RXDATAV 0x00100 + +#define REG_CLKDIV 0x10 +#define REG_CLKDIV_DIV__MASK 0x001ff +#define REG_CLKDIV_DIV(div) MASK_VAL(REG_CLKDIV_DIV__MASK, (div)) + +#define REG_SADDR 0x14 +#define REG_SADDRMASK 0x18 +#define REG_RXDATA 0x1c +#define REG_RXDATAP 0x20 +#define REG_TXDATA 0x24 +#define REG_IF 0x28 +#define REG_IF_START 0x00001 +#define REG_IF_RSTART 0x00002 +#define REG_IF_ADDR 0x00004 +#define REG_IF_TXC 0x00008 +#define REG_IF_TXBL 0x00010 +#define REG_IF_RXDATAV 0x00020 +#define REG_IF_ACK 0x00040 +#define REG_IF_NACK 0x00080 +#define REG_IF_MSTOP 0x00100 +#define REG_IF_ARBLOST 0x00200 +#define REG_IF_BUSERR 0x00400 +#define REG_IF_BUSHOLD 0x00800 +#define REG_IF_TXOF 0x01000 +#define REG_IF_RXUF 0x02000 +#define REG_IF_BITO 0x04000 +#define REG_IF_CLTO 0x08000 +#define REG_IF_SSTOP 0x10000 + +#define REG_IFS 0x2c +#define REG_IFC 0x30 +#define REG_IFC__MASK 0x1ffcf + +#define REG_IEN 0x34 + +#define REG_ROUTE 0x38 +#define REG_ROUTE_SDAPEN 0x00001 +#define REG_ROUTE_SCLPEN 0x00002 +#define REG_ROUTE_LOCATION__MASK 0x00700 +#define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n)) + +struct efm32_i2c_ddata { + struct i2c_adapter adapter; + + struct clk *clk; + void __iomem *base; + unsigned int irq; + u8 location; + unsigned long frequency; + + /* transfer data */ + struct completion done; + struct i2c_msg *msgs; + size_t num_msgs; + size_t current_word, current_msg; + int retval; +}; + +static u32 efm32_i2c_read32(struct efm32_i2c_ddata *ddata, unsigned of= fset) +{ + return readl(ddata->base + offset); +} + +static void efm32_i2c_write32(struct efm32_i2c_ddata *ddata, + unsigned offset, u32 value) +{ + writel(value, ddata->base + offset); +} + +static void efm32_i2c_send_next_msg(struct efm32_i2c_ddata *ddata) +{ + struct i2c_msg *cur_msg =3D &ddata->msgs[ddata->current_msg]; + + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_START); + efm32_i2c_write32(ddata, REG_TXDATA, cur_msg->addr << 1 | + (cur_msg->flags & I2C_M_RD ? 1 : 0)); +} + +static void efm32_i2c_send_next_byte(struct efm32_i2c_ddata *ddata) +{ + struct i2c_msg *cur_msg =3D &ddata->msgs[ddata->current_msg]; + if (ddata->current_word >=3D cur_msg->len) { + /* cur_msg completely transferred */ + ddata->current_word =3D 0; + ddata->current_msg +=3D 1; + + if (ddata->current_msg >=3D ddata->num_msgs) { + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); + complete(&ddata->done); + } else { + efm32_i2c_send_next_msg(ddata); + } + } else { + efm32_i2c_write32(ddata, REG_TXDATA, + cur_msg->buf[ddata->current_word++]); + } +} + +static void efm32_i2c_recv_next_byte(struct efm32_i2c_ddata *ddata) +{ + struct i2c_msg *cur_msg =3D &ddata->msgs[ddata->current_msg]; + + cur_msg->buf[ddata->current_word] =3D efm32_i2c_read32(ddata, REG_RXD= ATA); + ddata->current_word +=3D 1; + if (ddata->current_word >=3D cur_msg->len) { + /* cur_msg completely transferred */ + ddata->current_word =3D 0; + ddata->current_msg +=3D 1; + + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_NACK); + + if (ddata->current_msg >=3D ddata->num_msgs) { + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); + complete(&ddata->done); + } else { + efm32_i2c_send_next_msg(ddata); + } + } else { + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ACK); + } +} + +static irqreturn_t efm32_i2c_irq(int irq, void *dev_id) +{ + struct efm32_i2c_ddata *ddata =3D dev_id; + struct i2c_msg *cur_msg =3D &ddata->msgs[ddata->current_msg]; + u32 irqflag =3D efm32_i2c_read32(ddata, REG_IF); + u32 state =3D efm32_i2c_read32(ddata, REG_STATE); + + efm32_i2c_write32(ddata, REG_IFC, irqflag & REG_IFC__MASK); + + switch (state & REG_STATE_STATE__MASK) { + case REG_STATE_STATE_IDLE: + /* arbitration lost? */ + ddata->retval =3D -EAGAIN; + complete(&ddata->done); + break; + case REG_STATE_STATE_WAIT: + /* + * huh, this shouldn't happen. + * Reset hardware state and get out + */ + ddata->retval =3D -EIO; + efm32_i2c_write32(ddata, REG_CMD, + REG_CMD_STOP | REG_CMD_ABORT | + REG_CMD_CLEARTX | REG_CMD_CLEARPC); + complete(&ddata->done); + break; + case REG_STATE_STATE_START: + /* "caller" is expected to send an address */ + break; + case REG_STATE_STATE_ADDR: + /* wait for Ack or NAck of slave */ + break; + case REG_STATE_STATE_ADDRACK: + if (state & REG_STATE_NACKED) { + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); + ddata->retval =3D -ENXIO; + complete(&ddata->done); + } else if (cur_msg->flags & I2C_M_RD) { + /* wait for slave to send first data byte */ + } else { + efm32_i2c_send_next_byte(ddata); + } + break; + case REG_STATE_STATE_DATA: + if (cur_msg->flags & I2C_M_RD) { + efm32_i2c_recv_next_byte(ddata); + } else { + /* wait for Ack or Nack of slave */ + } + break; + case REG_STATE_STATE_DATAACK: + if (state & REG_STATE_NACKED) { + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); + complete(&ddata->done); + } else { + efm32_i2c_send_next_byte(ddata); + } + } + + return IRQ_HANDLED; +} + +static int efm32_i2c_master_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct efm32_i2c_ddata *ddata =3D i2c_get_adapdata(adap); + int ret; + + if (ddata->msgs) + return -EBUSY; + + ddata->msgs =3D msgs; + ddata->num_msgs =3D num; + ddata->current_word =3D 0; + ddata->current_msg =3D 0; + ddata->retval =3D -EIO; + + reinit_completion(&ddata->done); + + dev_dbg(&ddata->adapter.dev, "state: %08x, status: %08x\n", + efm32_i2c_read32(ddata, REG_STATE), + efm32_i2c_read32(ddata, REG_STATUS)); + + efm32_i2c_send_next_msg(ddata); + + wait_for_completion(&ddata->done); + + if (ddata->current_msg >=3D ddata->num_msgs) + ret =3D ddata->num_msgs; + else + ret =3D ddata->retval; + + ddata->msgs =3D NULL; + + return ret; +} + +static u32 efm32_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm efm32_i2c_algo =3D { + .master_xfer =3D efm32_i2c_master_xfer, + .functionality =3D efm32_i2c_functionality, +}; + +static u32 efm32_i2c_get_configured_location(struct efm32_i2c_ddata *d= data) +{ + u32 reg =3D efm32_i2c_read32(ddata, REG_ROUTE); + + return (reg & REG_ROUTE_LOCATION__MASK) >> + __ffs(REG_ROUTE_LOCATION__MASK); +} + +static int efm32_i2c_probe(struct platform_device *pdev) +{ + struct efm32_i2c_ddata *ddata; + struct resource *res; + unsigned long rate; + struct device_node *np =3D pdev->dev.of_node; + u32 location, frequency; + int ret; + u32 clkdiv; + + if (!np) + return -EINVAL; + + ddata =3D devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) { + dev_dbg(&pdev->dev, "failed to allocate private data\n"); + return -ENOMEM; + } + platform_set_drvdata(pdev, ddata); + + init_completion(&ddata->done); + strlcpy(ddata->adapter.name, pdev->name, sizeof(ddata->adapter.name))= ; + ddata->adapter.owner =3D THIS_MODULE; + ddata->adapter.algo =3D &efm32_i2c_algo; + ddata->adapter.dev.parent =3D &pdev->dev; + ddata->adapter.dev.of_node =3D pdev->dev.of_node; + i2c_set_adapdata(&ddata->adapter, ddata); + + ddata->clk =3D devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(ddata->clk)) { + ret =3D PTR_ERR(ddata->clk); + dev_err(&pdev->dev, "failed to get clock: %d\n", ret); + return ret; + } + + res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "failed to determine base address\n"); + return -ENODEV; + } + + if (resource_size(res) < 0x42) { + dev_err(&pdev->dev, "memory resource too small\n"); + return -EINVAL; + } + + ddata->base =3D devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(ddata->base)) + return PTR_ERR(ddata->base); + + ret =3D platform_get_irq(pdev, 0); + if (ret <=3D 0) { + dev_err(&pdev->dev, "failed to get irq (%d)\n", ret); + if (!ret) + ret =3D -EINVAL; + return ret; + } + + ddata->irq =3D ret; + + ret =3D clk_prepare_enable(ddata->clk); + if (ret < 0) { + dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret); + return ret; + } + + ret =3D of_property_read_u32(np, "efm32,location", &location); + if (!ret) { + dev_dbg(&pdev->dev, "using location %u\n", location); + } else { + /* default to location configured in hardware */ + location =3D efm32_i2c_get_configured_location(ddata); + + dev_info(&pdev->dev, "fall back to location %u\n", location); + } + + ddata->location =3D location; + + ret =3D of_property_read_u32(np, "clock-frequency", &frequency); + if (!ret) { + dev_dbg(&pdev->dev, "using frequency %u\n", frequency); + } else { + frequency =3D 100000; + dev_info(&pdev->dev, "defaulting to 100 kHz\n"); + } + ddata->frequency =3D frequency; + + rate =3D clk_get_rate(ddata->clk); + if (!rate) { + dev_err(&pdev->dev, "there is no input clock available\n"); + ret =3D -EINVAL; + goto err_disable_clk; + } + clkdiv =3D DIV_ROUND_UP(rate, 8 * ddata->frequency) - 1; + if (clkdiv >=3D 0x200) { + dev_err(&pdev->dev, + "input clock too fast (%lu) to divide down to bus freq (%lu)", + rate, ddata->frequency); + ret =3D -EINVAL; + goto err_disable_clk; + } + + dev_dbg(&pdev->dev, "input clock =3D %lu, bus freq =3D %lu, clkdiv =3D= %lu\n", + rate, ddata->frequency, (unsigned long)clkdiv); + efm32_i2c_write32(ddata, REG_CLKDIV, REG_CLKDIV_DIV(clkdiv)); + + efm32_i2c_write32(ddata, REG_ROUTE, REG_ROUTE_SDAPEN | + REG_ROUTE_SCLPEN | + REG_ROUTE_LOCATION(ddata->location)); + + efm32_i2c_write32(ddata, REG_CTRL, REG_CTRL_EN | + REG_CTRL_BITO_160PCC | 0 * REG_CTRL_GIBITO); + + efm32_i2c_write32(ddata, REG_IFC, REG_IFC__MASK); + efm32_i2c_write32(ddata, REG_IEN, REG_IF_TXC | REG_IF_ACK | REG_IF_NA= CK + | REG_IF_ARBLOST | REG_IF_BUSERR | REG_IF_RXDATAV); + + /* to make bus idle */ + efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ABORT); + + ret =3D request_irq(ddata->irq, efm32_i2c_irq, 0, DRIVER_NAME, ddata)= ; + if (ret < 0) { + dev_err(&pdev->dev, "failed to request irq (%d)\n", ret); + return ret; + } + + ret =3D i2c_add_adapter(&ddata->adapter); + if (ret) { + dev_err(&pdev->dev, "failed to add i2c adapter (%d)\n", ret); + free_irq(ddata->irq, ddata); + +err_disable_clk: + clk_disable_unprepare(ddata->clk); + } + return ret; +} + +static int efm32_i2c_remove(struct platform_device *pdev) +{ + struct efm32_i2c_ddata *ddata =3D platform_get_drvdata(pdev); + + i2c_del_adapter(&ddata->adapter); + free_irq(ddata->irq, ddata); + clk_disable_unprepare(ddata->clk); + + return 0; +} + +static const struct of_device_id efm32_i2c_dt_ids[] =3D { + { + .compatible =3D "efm32,i2c", + }, { + /* sentinel */ + } +}; +MODULE_DEVICE_TABLE(of, efm32_i2c_dt_ids); + +static struct platform_driver efm32_i2c_driver =3D { + .probe =3D efm32_i2c_probe, + .remove =3D efm32_i2c_remove, + + .driver =3D { + .name =3D DRIVER_NAME, + .owner =3D THIS_MODULE, + .of_match_table =3D efm32_i2c_dt_ids, + }, +}; +module_platform_driver(efm32_i2c_driver); + +MODULE_AUTHOR("Uwe Kleine-Koenig "); +MODULE_DESCRIPTION("EFM32 i2c driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" DRIVER_NAME); --=20 1.9.1