--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the Renesas RZ/V2M I2C unit
+ *
+ * Copyright (C) 2016-2022 Renesas Electronics Corporation
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/i2c.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+/* Register offsets */
+#define IICB0DAT 0x00 /* Data Register */
+#define IICB0CTL0 0x08 /* Control Register 0 */
+#define IICB0TRG 0x0C /* Trigger Register */
+#define IICB0STR0 0x10 /* Status Register 0 */
+#define IICB0CTL1 0x20 /* Control Register 1 */
+#define IICB0WL 0x24 /* Low Level Width Setting Reg */
+#define IICB0WH 0x28 /* How Level Width Setting Reg */
+
+/* IICB0CTL0 */
+#define IICB0IICE BIT(7) /* I2C Enable */
+#define IICB0SLWT BIT(1) /* Interrupt Request Timing */
+#define IICB0SLAC BIT(0) /* Acknowledge */
+
+/* IICB0TRG */
+#define IICB0WRET BIT(2) /* Quit Wait Trigger */
+#define IICB0STT BIT(1) /* Create Start Condition Trigger */
+#define IICB0SPT BIT(0) /* Create Stop Condition Trigger */
+
+/* IICB0STR0 */
+#define IICB0SSAC BIT(8) /* Ack Flag */
+#define IICB0SSBS BIT(6) /* Bus Flag */
+#define IICB0SSSP BIT(4) /* Stop Condition Flag */
+
+/* IICB0CTL1 */
+#define IICB0MDSC BIT(7) /* Bus Mode */
+#define IICB0SLSE BIT(1) /* Start condition output */
+
+#define bit_setl(addr, val) writel(readl(addr) | (val), (addr))
+#define bit_clrl(addr, val) writel(readl(addr) & ~(val), (addr))
+
+struct rzv2m_i2c_priv {
+ void __iomem *base;
+ struct i2c_adapter adap;
+ struct clk *clk;
+ int bus_mode;
+ struct completion msg_tia_done;
+ u32 iicb0wl;
+ u32 iicb0wh;
+};
+
+enum bcr_index {
+ RZV2M_I2C_100K = 0,
+ RZV2M_I2C_400K,
+};
+
+struct bitrate_config {
+ unsigned int percent_low;
+ unsigned int min_hold_time_ns;
+};
+
+static const struct bitrate_config bitrate_configs[] = {
+ [RZV2M_I2C_100K] = { 47, 3450 },
+ [RZV2M_I2C_400K] = { 52, 900 },
+};
+
+static irqreturn_t rzv2m_i2c_tia_irq_handler(int this_irq, void *dev_id)
+{
+ struct rzv2m_i2c_priv *priv = dev_id;
+
+ complete(&priv->msg_tia_done);
+
+ return IRQ_HANDLED;
+}
+
+/* Calculate IICB0WL and IICB0WH */
+static int rzv2m_i2c_clock_calculate(struct device *dev,
+ struct rzv2m_i2c_priv *priv)
+{
+ const struct bitrate_config *config;
+ unsigned int hold_time_ns;
+ unsigned int total_pclks;
+ unsigned int trf_pclks;
+ unsigned long pclk_hz;
+ struct i2c_timings t;
+ u32 trf_ns;
+
+ i2c_parse_fw_timings(dev, &t, true);
+
+ pclk_hz = clk_get_rate(priv->clk);
+ total_pclks = pclk_hz / t.bus_freq_hz;
+
+ trf_ns = t.scl_rise_ns + t.scl_fall_ns;
+ trf_pclks = mul_u64_u32_div(pclk_hz, trf_ns, NSEC_PER_SEC);
+
+ /* Config setting */
+ switch (t.bus_freq_hz) {
+ case I2C_MAX_FAST_MODE_FREQ:
+ priv->bus_mode = RZV2M_I2C_400K;
+ break;
+ case I2C_MAX_STANDARD_MODE_FREQ:
+ priv->bus_mode = RZV2M_I2C_100K;
+ break;
+ default:
+ dev_err(dev, "transfer speed is invalid\n");
+ return -EINVAL;
+ }
+ config = &bitrate_configs[priv->bus_mode];
+
+ /* IICB0WL = (percent_low / Transfer clock) x PCLK */
+ priv->iicb0wl = total_pclks * config->percent_low / 100;
+ if (priv->iicb0wl > (BIT(10) - 1))
+ return -EINVAL;
+
+ /* IICB0WH = ((percent_high / Transfer clock) x PCLK) - (tR + tF) */
+ priv->iicb0wh = total_pclks - priv->iicb0wl - trf_pclks;
+ if (priv->iicb0wh > (BIT(10) - 1))
+ return -EINVAL;
+
+ /*
+ * Data hold time must be less than 0.9us in fast mode and
+ * 3.45us in standard mode.
+ * Data hold time = IICB0WL[9:2] / PCLK
+ */
+ hold_time_ns = div64_ul((u64)(priv->iicb0wl >> 2) * NSEC_PER_SEC, pclk_hz);
+ if (hold_time_ns > config->min_hold_time_ns) {
+ dev_err(dev, "data hold time %dns is over %dns\n",
+ hold_time_ns, config->min_hold_time_ns);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void rzv2m_i2c_init(struct rzv2m_i2c_priv *priv)
+{
+ u32 i2c_ctl0;
+ u32 i2c_ctl1;
+
+ /* i2c disable */
+ writel(0, priv->base + IICB0CTL0);
+
+ /* IICB0CTL1 setting */
+ i2c_ctl1 = IICB0SLSE;
+ if (priv->bus_mode == RZV2M_I2C_400K)
+ i2c_ctl1 |= IICB0MDSC;
+ writel(i2c_ctl1, priv->base + IICB0CTL1);
+
+ /* IICB0WL IICB0WH setting */
+ writel(priv->iicb0wl, priv->base + IICB0WL);
+ writel(priv->iicb0wh, priv->base + IICB0WH);
+
+ /* i2c enable after setting */
+ i2c_ctl0 = IICB0SLWT | IICB0SLAC | IICB0IICE;
+ writel(i2c_ctl0, priv->base + IICB0CTL0);
+}
+
+static int rzv2m_i2c_write_with_ack(struct rzv2m_i2c_priv *priv, u32 data)
+{
+ unsigned long time_left;
+
+ reinit_completion(&priv->msg_tia_done);
+
+ writel(data, priv->base + IICB0DAT);
+
+ time_left = wait_for_completion_timeout(&priv->msg_tia_done,
+ priv->adap.timeout);
+ if (!time_left)
+ return -ETIMEDOUT;
+
+ /* Confirm ACK */
+ if ((readl(priv->base + IICB0STR0) & IICB0SSAC) != IICB0SSAC)
+ return -ENXIO;
+
+ return 0;
+}
+
+static int rzv2m_i2c_read_with_ack(struct rzv2m_i2c_priv *priv, u8 *data,
+ bool last)
+{
+ unsigned long time_left;
+ u32 data_tmp;
+
+ reinit_completion(&priv->msg_tia_done);
+
+ /* Interrupt request timing : 8th clock */
+ bit_clrl(priv->base + IICB0CTL0, IICB0SLWT);
+
+ /* Exit the wait state */
+ writel(IICB0WRET, priv->base + IICB0TRG);
+
+ /* Wait for transaction */
+ time_left = wait_for_completion_timeout(&priv->msg_tia_done,
+ priv->adap.timeout);
+ if (!time_left)
+ return -ETIMEDOUT;
+
+ if (last) {
+ /* Disable ACK */
+ bit_clrl(priv->base + IICB0CTL0, IICB0SLAC);
+
+ /* Read data*/
+ data_tmp = readl(priv->base + IICB0DAT);
+
+ /* Interrupt request timing : 9th clock */
+ bit_setl(priv->base + IICB0CTL0, IICB0SLWT);
+
+ /* Exit the wait state */
+ writel(IICB0WRET, priv->base + IICB0TRG);
+
+ /* Wait for transaction */
+ time_left = wait_for_completion_timeout(&priv->msg_tia_done,
+ priv->adap.timeout);
+ if (!time_left)
+ return -ETIMEDOUT;
+
+ /* Enable ACK */
+ bit_setl(priv->base + IICB0CTL0, IICB0SLAC);
+ } else {
+ /* Read data */
+ data_tmp = readl(priv->base + IICB0DAT);
+ }
+
+ *data = data_tmp;
+
+ return 0;
+}
+
+static int rzv2m_i2c_send(struct rzv2m_i2c_priv *priv, struct i2c_msg *msg,
+ unsigned int *count)
+{
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < msg->len; i++) {
+ ret = rzv2m_i2c_write_with_ack(priv, msg->buf[i]);
+ if (ret < 0)
+ return ret;
+ }
+ *count = i;
+
+ return 0;
+}
+
+static int rzv2m_i2c_receive(struct rzv2m_i2c_priv *priv, struct i2c_msg *msg,
+ unsigned int *count)
+{
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < msg->len; i++) {
+ ret = rzv2m_i2c_read_with_ack(priv, &msg->buf[i],
+ (msg->len - 1) == i);
+ if (ret < 0)
+ return ret;
+ }
+ *count = i;
+
+ return 0;
+}
+
+static int rzv2m_i2c_send_address(struct rzv2m_i2c_priv *priv,
+ struct i2c_msg *msg)
+{
+ u32 addr;
+ int ret;
+
+ if (msg->flags & I2C_M_TEN) {
+ /*
+ * 10-bit address
+ * addr_1: 5'b11110 | addr[9:8] | (R/nW)
+ * addr_2: addr[7:0]
+ */
+ addr = 0xf0 | ((msg->addr & GENMASK(9, 8)) >> 7);
+ addr |= !!(msg->flags & I2C_M_RD);
+ /* Send 1st address(extend code) */
+ ret = rzv2m_i2c_write_with_ack(priv, addr);
+ if (ret)
+ return ret;
+
+ /* Send 2nd address */
+ ret = rzv2m_i2c_write_with_ack(priv, msg->addr & 0xff);
+ } else {
+ /* 7-bit address */
+ addr = i2c_8bit_addr_from_msg(msg);
+ ret = rzv2m_i2c_write_with_ack(priv, addr);
+ }
+
+ return ret;
+}
+
+static int rzv2m_i2c_stop_condition(struct rzv2m_i2c_priv *priv)
+{
+ u32 value;
+
+ /* Send stop condition */
+ writel(IICB0SPT, priv->base + IICB0TRG);
+ return readl_poll_timeout(priv->base + IICB0STR0,
+ value, value & IICB0SSSP,
+ 100, jiffies_to_usecs(priv->adap.timeout));
+}
+
+static int rzv2m_i2c_master_xfer_msg(struct rzv2m_i2c_priv *priv,
+ struct i2c_msg *msg, int stop)
+{
+ unsigned int count = 0;
+ int ret, read = !!(msg->flags & I2C_M_RD);
+
+ /* Send start condition */
+ writel(IICB0STT, priv->base + IICB0TRG);
+
+ ret = rzv2m_i2c_send_address(priv, msg);
+ if (!ret) {
+ if (read)
+ ret = rzv2m_i2c_receive(priv, msg, &count);
+ else
+ ret = rzv2m_i2c_send(priv, msg, &count);
+
+ if (!ret && stop)
+ ret = rzv2m_i2c_stop_condition(priv);
+ }
+
+ if (ret == -ENXIO)
+ rzv2m_i2c_stop_condition(priv);
+ else if (ret < 0)
+ rzv2m_i2c_init(priv);
+ else
+ ret = count;
+
+ return ret;
+}
+
+static int rzv2m_i2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct rzv2m_i2c_priv *priv = i2c_get_adapdata(adap);
+ struct device *dev = priv->adap.dev.parent;
+ unsigned int i;
+ int ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret < 0)
+ return ret;
+
+ if (readl(priv->base + IICB0STR0) & IICB0SSBS) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ /* I2C main transfer */
+ for (i = 0; i < num; i++) {
+ ret = rzv2m_i2c_master_xfer_msg(priv, &msgs[i], i == (num - 1));
+ if (ret < 0)
+ goto out;
+ }
+ ret = num;
+
+out:
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+
+ return ret;
+}
+
+static u32 rzv2m_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
+ I2C_FUNC_10BIT_ADDR;
+}
+
+static const struct i2c_adapter_quirks rzv2m_i2c_quirks = {
+ .flags = I2C_AQ_NO_ZERO_LEN,
+};
+
+static struct i2c_algorithm rzv2m_i2c_algo = {
+ .master_xfer = rzv2m_i2c_master_xfer,
+ .functionality = rzv2m_i2c_func,
+};
+
+static int rzv2m_i2c_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rzv2m_i2c_priv *priv;
+ struct reset_control *rstc;
+ struct i2c_adapter *adap;
+ struct resource *res;
+ int irq, ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(dev, PTR_ERR(priv->clk), "Can't get clock\n");
+
+ rstc = devm_reset_control_get_shared(dev, NULL);
+ if (IS_ERR(rstc))
+ return dev_err_probe(dev, PTR_ERR(rstc), "Missing reset ctrl\n");
+ /*
+ * The reset also affects other HW that is not under the control
+ * of Linux. Therefore, all we can do is deassert the reset.
+ */
+ reset_control_deassert(rstc);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_irq(dev, irq, rzv2m_i2c_tia_irq_handler, 0,
+ dev_name(dev), priv);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Unable to request irq %d\n", irq);
+
+ adap = &priv->adap;
+ adap->nr = pdev->id;
+ adap->algo = &rzv2m_i2c_algo;
+ adap->quirks = &rzv2m_i2c_quirks;
+ adap->dev.parent = dev;
+ adap->owner = THIS_MODULE;
+ device_set_node(&adap->dev, dev_fwnode(dev));
+ i2c_set_adapdata(adap, priv);
+ strscpy(adap->name, pdev->name, sizeof(adap->name));
+ init_completion(&priv->msg_tia_done);
+
+ ret = rzv2m_i2c_clock_calculate(dev, priv);
+ if (ret < 0)
+ return ret;
+
+ pm_runtime_enable(dev);
+
+ pm_runtime_get_sync(dev);
+ rzv2m_i2c_init(priv);
+ pm_runtime_put(dev);
+
+ platform_set_drvdata(pdev, priv);
+
+ ret = i2c_add_numbered_adapter(adap);
+ if (ret < 0)
+ pm_runtime_disable(dev);
+
+ return ret;
+}
+
+static int rzv2m_i2c_remove(struct platform_device *pdev)
+{
+ struct rzv2m_i2c_priv *priv = platform_get_drvdata(pdev);
+ struct device *dev = priv->adap.dev.parent;
+
+ i2c_del_adapter(&priv->adap);
+ bit_clrl(priv->base + IICB0CTL0, IICB0IICE);
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+
+static int rzv2m_i2c_suspend(struct device *dev)
+{
+ struct rzv2m_i2c_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret < 0)
+ return ret;
+
+ bit_clrl(priv->base + IICB0CTL0, IICB0IICE);
+ pm_runtime_put(dev);
+
+ return 0;
+}
+
+static int rzv2m_i2c_resume(struct device *dev)
+{
+ struct rzv2m_i2c_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = rzv2m_i2c_clock_calculate(dev, priv);
+ if (ret < 0)
+ return ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret < 0)
+ return ret;
+
+ rzv2m_i2c_init(priv);
+ pm_runtime_put(dev);
+
+ return 0;
+}
+
+static const struct of_device_id rzv2m_i2c_ids[] = {
+ { .compatible = "renesas,rzv2m-i2c" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rzv2m_i2c_ids);
+
+static const struct dev_pm_ops rzv2m_i2c_pm_ops = {
+ SYSTEM_SLEEP_PM_OPS(rzv2m_i2c_suspend, rzv2m_i2c_resume)
+};
+
+static struct platform_driver rzv2m_i2c_driver = {
+ .driver = {
+ .name = "rzv2m-i2c",
+ .of_match_table = rzv2m_i2c_ids,
+ .pm = pm_sleep_ptr(&rzv2m_i2c_pm_ops),
+ },
+ .probe = rzv2m_i2c_probe,
+ .remove = rzv2m_i2c_remove,
+};
+module_platform_driver(rzv2m_i2c_driver);
+
+MODULE_DESCRIPTION("RZ/V2M I2C bus driver");
+MODULE_AUTHOR("Renesas Electronics Corporation");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
