On June 30, 2018 3:33:29 PM GMT+02:00, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: >Add Actions Semiconductor 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 | 477 +++++++++++++++++++++++++++++++++++ > 3 files changed, 485 insertions(+) > create mode 100644 drivers/i2c/busses/i2c-owl.c > >diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig >index 4f8df2ec87b1..8c8025f87ce4 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 "Actions Semiconductor 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 Semiconductor Owl SoC's. >+ > 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..144a249bf994 >--- /dev/null >+++ b/drivers/i2c/busses/i2c-owl.c >@@ -0,0 +1,477 @@ >+// SPDX-License-Identifier: GPL-2.0+ >+/* >+ * Actions Semiconductor 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/io.h> >+#include <linux/module.h> >+#include <linux/of_device.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 >+ >+/* 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) >+ >+#define OWL_I2C_MAX_RETRIES 50 >+ >+#define OWL_I2C_DEF_SPEED_HZ 100000 >+#define OWL_I2C_MAX_SPEED_HZ 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 *reg, unsigned int val, >bool state) >+{ >+ unsigned int regval; >+ >+ regval = readl(reg); >+ >+ if (state) >+ regval |= val; >+ else >+ regval &= ~val; >+ >+ writel(regval, reg); >+} >+ >+static int owl_i2c_reset(struct owl_i2c_dev *i2c_dev) >+{ >+ unsigned int val, timeout = 0; >+ >+ 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 50ms for FIFO reset complete */ >+ do { >+ val = readl(i2c_dev->base + OWL_I2C_REG_FIFOCTL); >+ if (!(val & (OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR))) >+ break; >+ mdelay(1); >+ } while (timeout++ < OWL_I2C_MAX_RETRIES); >+ >+ if (timeout > OWL_I2C_MAX_RETRIES) { >+ dev_err(&i2c_dev->adap.dev, "FIFO reset timeout"); >+ return -ETIMEDOUT; >+ } >+ >+ /* Clear status registers */ >+ writel(0, i2c_dev->base + OWL_I2C_REG_STAT); >+ >+ return 0; >+} >+ >+static int 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); >+ >+ return 0; >+} >+ >+static int owl_i2c_hw_init(struct owl_i2c_dev *i2c_dev) >+{ >+ int ret; >+ >+ /* Reset I2C controller */ >+ ret = owl_i2c_reset(i2c_dev); >+ if (ret) >+ return ret; >+ >+ /* Set bus frequency */ >+ return 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_dbg(&i2c_dev->adap.dev, "received NACK from device"); >+ goto stop; >+ } >+ >+ stat = readl(i2c_dev->base + OWL_I2C_REG_STAT); >+ if (stat & OWL_I2C_STAT_BEB) { >+ dev_dbg(&i2c_dev->adap.dev, "bus error"); >+ 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); >+ Here is a read-modify-write on ..._REG_STAT from interrupt context... >+ 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; >+ >+ /* Check for Arbitration lost */ >+ val = readl(i2c_dev->base + OWL_I2C_REG_STAT); >+ if (val & OWL_I2C_STAT_LAB) { >+ val &= ~OWL_I2C_STAT_LAB; >+ writel(val, i2c_dev->base + OWL_I2C_REG_STAT); ...and here is one from process context. Can they cross? If not, why? Either use some locking, or add a comment explaining why this is safe. >+ return -EAGAIN; >+ } >+ >+ /* Check for Bus busy */ >+ timeout = jiffies + OWL_I2C_TIMEOUT; >+ while (readl(i2c_dev->base + OWL_I2C_REG_STAT) & OWL_I2C_STAT_BBB) { >+ 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, idx; >+ >+ ret = owl_i2c_hw_init(i2c_dev); >+ if (ret) >+ return ret; >+ >+ 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); >+ >+ /* 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 */ >+ addr = i2c_8bit_addr_from_msg(&msgs[0]); >+ 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); >+ >+ addr = i2c_8bit_addr_from_msg(msg); >+ writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT); >+ >+ if (!(msg->flags & I2C_M_RD)) { >+ /* 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; >+ } >+ >+ /* Ignore 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; >+ } >+ >+ /* >+ * By default, 0 will be returned if interrupt occurred but no >+ * read or write happened. Else if msg_ptr equals to message length, >+ * message count will be returned. >+ */ Zero is never a valid return value for this function. It has to be either num or a negative error. So, this comment is bad, which makes me assume the code is too. I didn't bother to check any further... Cheers, Peter >+ if (i2c_dev->msg_ptr == msg->len) >+ ret = num; >+ >+ /* Disable I2C controller */ >+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, >+ OWL_I2C_CTL_EN, false); >+ >+ return ret; >+} >+ >+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_DEF_SPEED_HZ; >+ >+ /* We support only frequencies of 100k and 400k for now */ >+ if (i2c_dev->bus_freq != OWL_I2C_DEF_SPEED_HZ && >+ i2c_dev->bus_freq > OWL_I2C_MAX_SPEED_HZ) { >+ 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; >+ } >+ >+ return i2c_add_adapter(&i2c_dev->adap); >+ >+disable_clk: >+ clk_disable_unprepare(i2c_dev->clk); >+ >+ 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 Semiconductor Owl SoC's I2C driver"); >+MODULE_LICENSE("GPL");
