On Sat, Jun 23, 2018 at 7:11 PM, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > Add Actions Semi OWL family S900 I2C driver. > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > --- > drivers/i2c/busses/Kconfig | 7 + > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-owl.c | 459 +++++++++++++++++++++++++++++++++++ > 3 files changed, 467 insertions(+) > create mode 100644 drivers/i2c/busses/i2c-owl.c > > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index 4f8df2ec87b1..2062da17e33b 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -762,6 +762,13 @@ config I2C_OMAP > Like OMAP1510/1610/1710/5912 and OMAP242x. > For details see http://www.ti.com/omap. > > +config I2C_OWL > + tristate "OWL I2C Controller" > + depends on ARCH_ACTIONS || COMPILE_TEST > + help > + Say Y here if you want to use the I2C bus controller on > + the Actions Semi OWL SoCs. > + > config I2C_PASEMI > tristate "PA Semi SMBus interface" > depends on PPC_PASEMI && PCI > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index 5a869144a0c5..b71618f77880 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_MXS) += i2c-mxs.o > obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o > obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o > obj-$(CONFIG_I2C_OMAP) += i2c-omap.o > +obj-$(CONFIG_I2C_OWL) += i2c-owl.o > obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o > obj-$(CONFIG_I2C_PCA_PLATFORM) += i2c-pca-platform.o > obj-$(CONFIG_I2C_PMCMSP) += i2c-pmcmsp.o > diff --git a/drivers/i2c/busses/i2c-owl.c b/drivers/i2c/busses/i2c-owl.c > new file mode 100644 > index 000000000000..53100ddfb3cc > --- /dev/null > +++ b/drivers/i2c/busses/i2c-owl.c > @@ -0,0 +1,459 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * OWL SoC's I2C driver > + * > + * Copyright (c) 2014 Actions Semi Inc. > + * Author: David Liu <liuwei@xxxxxxxxxxxxxxxx> > + * > + * Copyright (c) 2018 Linaro Ltd. > + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > + */ > + > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/i2c.h> > +#include <linux/interrupt.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/io.h> > + > +/* I2C registers */ > +#define OWL_I2C_REG_CTL (0x0000) > +#define OWL_I2C_REG_CLKDIV (0x0004) > +#define OWL_I2C_REG_STAT (0x0008) > +#define OWL_I2C_REG_ADDR (0x000C) > +#define OWL_I2C_REG_TXDAT (0x0010) > +#define OWL_I2C_REG_RXDAT (0x0014) > +#define OWL_I2C_REG_CMD (0x0018) > +#define OWL_I2C_REG_FIFOCTL (0x001C) > +#define OWL_I2C_REG_FIFOSTAT (0x0020) > +#define OWL_I2C_REG_DATCNT (0x0024) > +#define OWL_I2C_REG_RCNT (0x0028) I don't understand why these have parents? > + > +/* I2Cx_CTL Bit Mask */ > +#define OWL_I2C_CTL_RB BIT(1) > +#define OWL_I2C_CTL_GBCC(x) (((x) & 0x3) << 2) > +#define OWL_I2C_CTL_GBCC_NONE OWL_I2C_CTL_GBCC(0) > +#define OWL_I2C_CTL_GBCC_START OWL_I2C_CTL_GBCC(1) > +#define OWL_I2C_CTL_GBCC_STOP OWL_I2C_CTL_GBCC(2) > +#define OWL_I2C_CTL_GBCC_RSTART OWL_I2C_CTL_GBCC(3) > +#define OWL_I2C_CTL_IRQE BIT(5) > +#define OWL_I2C_CTL_EN BIT(7) > +#define OWL_I2C_CTL_AE BIT(8) > +#define OWL_I2C_CTL_SHSM BIT(10) > + > +#define OWL_I2C_DIV_FACTOR(x) ((x) & 0xff) > + > +/* I2Cx_STAT Bit Mask */ > +#define OWL_I2C_STAT_RACK BIT(0) > +#define OWL_I2C_STAT_BEB BIT(1) > +#define OWL_I2C_STAT_IRQP BIT(2) > +#define OWL_I2C_STAT_LAB BIT(3) > +#define OWL_I2C_STAT_STPD BIT(4) > +#define OWL_I2C_STAT_STAD BIT(5) > +#define OWL_I2C_STAT_BBB BIT(6) > +#define OWL_I2C_STAT_TCB BIT(7) > +#define OWL_I2C_STAT_LBST BIT(8) > +#define OWL_I2C_STAT_SAMB BIT(9) > +#define OWL_I2C_STAT_SRGC BIT(10) > + > +/* I2Cx_CMD Bit Mask */ > +#define OWL_I2C_CMD_SBE BIT(0) > +#define OWL_I2C_CMD_RBE BIT(4) > +#define OWL_I2C_CMD_DE BIT(8) > +#define OWL_I2C_CMD_NS BIT(9) > +#define OWL_I2C_CMD_SE BIT(10) > +#define OWL_I2C_CMD_MSS BIT(11) > +#define OWL_I2C_CMD_WRS BIT(12) > +#define OWL_I2C_CMD_SECL BIT(15) > + > +#define OWL_I2C_CMD_AS(x) (((x) & 0x7) << 1) > +#define OWL_I2C_CMD_SAS(x) (((x) & 0x7) << 5) > + > +/* I2Cx_FIFOCTL Bit Mask */ > +#define OWL_I2C_FIFOCTL_NIB BIT(0) > +#define OWL_I2C_FIFOCTL_RFR BIT(1) > +#define OWL_I2C_FIFOCTL_TFR BIT(2) > + > +/* I2Cc_FIFOSTAT Bit Mask */ > +#define OWL_I2C_FIFOSTAT_RNB BIT(1) > +#define OWL_I2C_FIFOSTAT_RFE BIT(2) > +#define OWL_I2C_FIFOSTAT_TFF BIT(5) > +#define OWL_I2C_FIFOSTAT_TFD GENMASK(23, 16) > +#define OWL_I2C_FIFOSTAT_RFD GENMASK(15, 8) > + > +/* I2C bus timeout */ > +#define OWL_I2C_TIMEOUT (msecs_to_jiffies(4 * 1000)) Ditto. > + > +#define OWL_I2C_DEFAULT_SPEED 100000 > +#define OWL_I2C_MAX_SPEED 400000 > + > +struct owl_i2c_dev { > + struct i2c_adapter adap; > + struct i2c_msg *msg; > + struct completion msg_complete; > + struct clk *clk; > + void __iomem *base; > + unsigned long clk_rate; > + u32 bus_freq; > + u32 msg_ptr; > +}; > + > +static void owl_i2c_update_reg(void __iomem *base, unsigned int val, bool state) > +{ > + unsigned int regval; > + > + regval = readl(base); > + > + if (state) > + regval |= val; > + else > + regval &= ~val; > + > + writel(regval, base); > +} > + > +static void owl_i2c_reset(struct owl_i2c_dev *i2c_dev) > +{ > + unsigned int val; > + > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > + OWL_I2C_CTL_EN, false); > + mdelay(1); > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > + OWL_I2C_CTL_EN, true); > + > + /* Reset FIFO */ > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL, > + OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR, > + true); > + > + /* Wait until FIFO reset complete */ > + do { > + val = readl(i2c_dev->base + OWL_I2C_REG_FIFOCTL); > + if (!(val & (OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR))) > + break; > + } while (1); No way. Get rid of infinite loop. > + > + /* Clear status registers */ > + writel(0, i2c_dev->base + OWL_I2C_REG_STAT); > +} > + > +static void owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev) > +{ > + unsigned int val; > + > + val = (i2c_dev->clk_rate + i2c_dev->bus_freq * 16 - 1) / > + (i2c_dev->bus_freq * 16); > + > + /* Set clock divider factor */ > + writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV); > +} > + > +static void owl_i2c_hw_init(struct owl_i2c_dev *i2c_dev) > +{ > + /* Reset I2C controller */ > + owl_i2c_reset(i2c_dev); > + > + /* Set bus frequency */ > + owl_i2c_set_freq(i2c_dev); > +} > + > +static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > +{ > + struct owl_i2c_dev *i2c_dev = _dev; > + struct i2c_msg *msg = i2c_dev->msg; > + unsigned int stat, fifostat; > + > + fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT); > + if (fifostat & OWL_I2C_FIFOSTAT_RNB) { > + dev_warn(&i2c_dev->adap.dev, "received NACK from device"); And if it happens hundreds times in a row? > + owl_i2c_reset(i2c_dev); > + goto stop; > + } > + > + stat = readl(i2c_dev->base + OWL_I2C_REG_STAT); > + if (stat & OWL_I2C_STAT_BEB) { > + dev_warn(&i2c_dev->adap.dev, "bus error"); Ditto. > + owl_i2c_reset(i2c_dev); > + goto stop; > + } > + > + /* Handle FIFO read */ > + if (msg->flags & I2C_M_RD) { > + while ((readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) & > + OWL_I2C_FIFOSTAT_RFE) && > + (i2c_dev->msg_ptr < msg->len)) { > + msg->buf[i2c_dev->msg_ptr++] = readl(i2c_dev->base + > + OWL_I2C_REG_RXDAT); > + } > + } else { > + /* Handle the remaining bytes which were not sent */ > + while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) & > + OWL_I2C_FIFOSTAT_TFF) && > + i2c_dev->msg_ptr < msg->len) { > + writel(msg->buf[i2c_dev->msg_ptr++], i2c_dev->base + > + OWL_I2C_REG_TXDAT); > + } > + } > + > +stop: > + /* Clear pending interrupts */ > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT, > + OWL_I2C_STAT_IRQP, true); > + > + complete_all(&i2c_dev->msg_complete); > + > + return IRQ_HANDLED; > +} > + > +static u32 owl_i2c_func(struct i2c_adapter *adap) > +{ > + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; > +} > + > +static int owl_i2c_check_bus_busy(struct i2c_adapter *adap) > +{ > + struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap); > + unsigned long timeout; > + unsigned int val; > + > + timeout = jiffies + OWL_I2C_TIMEOUT; > + while (1) { Red flag! Use do { ... } while (time_after(...)); instead. > + val = readl(i2c_dev->base + OWL_I2C_REG_STAT); > + > + /* Check for Arbitration lost */ > + if (val & OWL_I2C_STAT_LAB) { > + val &= ~OWL_I2C_STAT_LAB; > + writel(val, i2c_dev->base + OWL_I2C_REG_STAT); > + return -EAGAIN; > + } > + > + /* Check for Bus busy */ > + if (!(val & OWL_I2C_STAT_BBB)) > + break; > + > + if (time_after(jiffies, timeout)) { > + dev_err(&adap->dev, "Bus busy timeout"); > + return -ETIMEDOUT; > + } > + } > + > + return 0; > +} > + > +static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > + int num) > +{ > + struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap); > + struct i2c_msg *msg; > + unsigned long time_left; > + unsigned int i2c_cmd; > + unsigned int addr; > + int ret = 0, idx; > + > + owl_i2c_hw_init(i2c_dev); > + > + ret = owl_i2c_check_bus_busy(adap); > + if (ret) > + return ret; > + > + reinit_completion(&i2c_dev->msg_complete); > + > + /* Enable I2C controller interrupt */ > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > + OWL_I2C_CTL_IRQE, true); > + > + /* > + * Select: FIFO enable, Master mode, Stop enable, Data count enable, > + * Send start bit > + */ > + i2c_cmd = (OWL_I2C_CMD_SECL | OWL_I2C_CMD_MSS | OWL_I2C_CMD_SE > + | OWL_I2C_CMD_NS | OWL_I2C_CMD_DE | OWL_I2C_CMD_SBE); > + > + addr = (msgs[0].addr & 0x7f) << 1; > + > + /* Handle repeated start condition */ > + if (num > 1) { > + /* Set internal address length and enable repeated start */ > + i2c_cmd |= (OWL_I2C_CMD_AS(msgs[0].len + 1) > + | OWL_I2C_CMD_SAS(1) | OWL_I2C_CMD_RBE); > + > + /* Write slave address */ > + writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT); > + > + /* Write internal register address */ > + for (idx = 0; idx < msgs[0].len; idx++) > + writel(msgs[0].buf[idx], i2c_dev->base + > + OWL_I2C_REG_TXDAT); > + > + msg = &msgs[1]; > + } else { > + /* Set address length */ > + i2c_cmd |= OWL_I2C_CMD_AS(1); > + msg = &msgs[0]; > + } > + > + i2c_dev->msg = msg; > + i2c_dev->msg_ptr = 0; > + > + /* Set data count for the message */ > + writel(msg->len, i2c_dev->base + OWL_I2C_REG_DATCNT); > + > + if (msg->flags & I2C_M_RD) { > + writel((addr | 1), i2c_dev->base + OWL_I2C_REG_TXDAT); > + } else { > + writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT); Don't we have a helper to construct 8-bit address? > + > + /* Write data to FIFO */ > + for (idx = 0; idx < msg->len; idx++) { > + /* Check for FIFO full */ > + if (readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) > + & OWL_I2C_FIFOSTAT_TFF) > + break; > + > + writel(msg->buf[idx], > + i2c_dev->base + OWL_I2C_REG_TXDAT); > + } > + > + i2c_dev->msg_ptr = idx; > + } > + > + /* Ingore the NACK if needed */ > + if (msg->flags & I2C_M_IGNORE_NAK) > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL, > + OWL_I2C_FIFOCTL_NIB, true); > + else > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL, > + OWL_I2C_FIFOCTL_NIB, false); > + > + /* Start the transfer */ > + writel(i2c_cmd, i2c_dev->base + OWL_I2C_REG_CMD); > + > + time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > + adap->timeout); > + if (time_left == 0) { > + dev_err(&adap->dev, "Transaction timed out"); > + /* Send stop condition and release the bus */ > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > + OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB, true); > + ret = -ETIMEDOUT; > + } > + > + /* Disable I2C controller */ > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > + OWL_I2C_CTL_EN, false); > + > + return i2c_dev->msg_ptr; > +} > + > +static const struct i2c_algorithm owl_i2c_algorithm = { > + .master_xfer = owl_i2c_master_xfer, > + .functionality = owl_i2c_func > +}; > + > +static const struct i2c_adapter_quirks owl_i2c_quirks = { > + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST, > + .max_read_len = 240, > + .max_write_len = 240, > + .max_comb_1st_msg_len = 6, > + .max_comb_2nd_msg_len = 240 > +}; > + > +static int owl_i2c_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct owl_i2c_dev *i2c_dev; > + struct resource *res; > + int ret, irq; > + > + i2c_dev = devm_kzalloc(dev, sizeof(*i2c_dev), 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); > + > + irq = platform_get_irq(pdev, 0); > + if (irq < 0) { > + dev_err(dev, "failed to get IRQ number\n"); > + return irq; > + } > + > + if (of_property_read_u32(dev->of_node, "clock-frequency", > + &i2c_dev->bus_freq)) > + i2c_dev->bus_freq = OWL_I2C_DEFAULT_SPEED; > + > + /* We support only frequencies of 100k and 400k for now */ > + if (i2c_dev->bus_freq != OWL_I2C_DEFAULT_SPEED && > + i2c_dev->bus_freq > OWL_I2C_MAX_SPEED) { > + dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq); > + return -EINVAL; > + } > + > + i2c_dev->clk = devm_clk_get(dev, NULL); > + if (IS_ERR(i2c_dev->clk)) { > + dev_err(dev, "failed to get clock\n"); > + return PTR_ERR(i2c_dev->clk); > + } > + > + ret = clk_prepare_enable(i2c_dev->clk); > + if (ret) > + return ret; > + > + i2c_dev->clk_rate = clk_get_rate(i2c_dev->clk); > + if (!i2c_dev->clk_rate) { > + dev_err(dev, "input clock rate should not be zero\n"); > + ret = -EINVAL; > + goto disable_clk; > + } > + > + init_completion(&i2c_dev->msg_complete); > + i2c_dev->adap.owner = THIS_MODULE; > + i2c_dev->adap.algo = &owl_i2c_algorithm; > + i2c_dev->adap.timeout = OWL_I2C_TIMEOUT; > + i2c_dev->adap.quirks = &owl_i2c_quirks; > + i2c_dev->adap.dev.parent = dev; > + i2c_dev->adap.dev.of_node = dev->of_node; > + snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name), > + "%s", "OWL I2C adapter"); > + i2c_set_adapdata(&i2c_dev->adap, i2c_dev); > + > + platform_set_drvdata(pdev, i2c_dev); > + > + ret = devm_request_irq(dev, irq, owl_i2c_interrupt, 0, pdev->name, > + i2c_dev); > + if (ret) { > + dev_err(dev, "failed to request irq %d\n", irq); > + goto disable_clk; > + } > + > + ret = i2c_add_adapter(&i2c_dev->adap); > +disable_clk: > + if (ret) > + clk_disable_unprepare(i2c_dev->clk); > + > + return ret; Can't we go with more usual patter, i.e. ret = ...; if (ret) goto err_handling; return 0; err_handling: ... return ret; ? > +} > + > +static const struct of_device_id owl_i2c_of_match[] = { > + {.compatible = "actions,s900-i2c"}, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, owl_i2c_of_match); > + > +static struct platform_driver owl_i2c_driver = { > + .probe = owl_i2c_probe, > + .driver = { > + .name = "owl-i2c", > + .of_match_table = of_match_ptr(owl_i2c_of_match), > + }, > +}; > +module_platform_driver(owl_i2c_driver); > + > +MODULE_AUTHOR("David Liu <liuwei@xxxxxxxxxxxxxxxx>"); > +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>"); > +MODULE_DESCRIPTION("Actions Semi OWL SoCs I2C driver"); > +MODULE_LICENSE("GPL"); > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko
