pwm: Add support for R-Car PWM Timer
This patch adds support for R-Car SoCs PWM Timer. The PWM timer of
R-Car H2 has 7 channels. So, we can use the channels if we describe
device tree nodes.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c
new file mode 100644
index 0000000..6e99a63
--- /dev/null
+++ b/drivers/pwm/pwm-rcar.c
@@ -0,0 +1,274 @@
+/*
+ * R-Car PWM Timer driver
+ *
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define RCAR_PWM_MAX_DIVISION 24
+#define RCAR_PWM_MAX_CYCLE 1023
+
+#define RCAR_PWMCR 0x00
+#define RCAR_PWMCR_CC0_MASK 0x000f0000
+#define RCAR_PWMCR_CC0_SHIFT 16
+#define RCAR_PWMCR_CCMD BIT(15)
+#define RCAR_PWMCR_SYNC BIT(11)
+#define RCAR_PWMCR_SS0 BIT(4)
+#define RCAR_PWMCR_EN0 BIT(0)
+
+#define RCAR_PWMCNT 0x04
+#define RCAR_PWMCNT_CYC0_MASK 0x03ff0000
+#define RCAR_PWMCNT_CYC0_SHIFT 16
+#define RCAR_PWMCNT_PH0_MASK 0x000003ff
+#define RCAR_PWMCNT_PH0_SHIFT 0
+
+struct rcar_pwm_chip {
+ struct pwm_chip chip;
+ void __iomem *base;
+ struct clk *clk;
+};
+
+static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct rcar_pwm_chip, chip);
+}
+
+static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
+ unsigned int offset)
+{
+ writel(data, rp->base + offset);
+}
+
+static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
+{
+ return readl(rp->base + offset);
+}
+
+static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
+ unsigned int offset)
+{
+ u32 value;
+
+ value = rcar_pwm_read(rp, offset);
+ value &= ~mask;
+ value |= data & mask;
+ rcar_pwm_write(rp, value, offset);
+}
+
+static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
+{
+ unsigned long clk_rate = clk_get_rate(rp->clk);
+ unsigned long long max; /* max cycle / nanoseconds */
+ unsigned int div;
+
+ if (clk_rate == 0)
+ return -EINVAL;
+
+ for (div = 0; div <= RCAR_PWM_MAX_DIVISION; div++) {
+ max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE *
+ (1 << div);
+ do_div(max, clk_rate);
+ if (period_ns < max)
+ break;
+ }
+
+ return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
+}
+
+static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
+ unsigned int div)
+{
+ u32 value;
+
+ value = rcar_pwm_read(rp, RCAR_PWMCR);
+ value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
+
+ if (div & 1)
+ value |= RCAR_PWMCR_CCMD;
+
+ div >>= 1;
+
+ value |= div << RCAR_PWMCR_CC0_SHIFT;
+ rcar_pwm_write(rp, value, RCAR_PWMCR);
+}
+
+static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
+ int period_ns)
+{
+ unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */
+ unsigned long clk_rate = clk_get_rate(rp->clk);
+ u32 cyc, ph;
+
+ one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
+ do_div(one_cycle, clk_rate);
+
+ tmp = period_ns * 100ULL;
+ do_div(tmp, one_cycle);
+ cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
+
+ tmp = duty_ns * 100ULL;
+ do_div(tmp, one_cycle);
+ ph = tmp & RCAR_PWMCNT_PH0_MASK;
+
+ /* Avoid prohibited setting */
+ if (cyc == 0 || ph == 0)
+ return -EINVAL;
+
+ rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
+
+ return 0;
+}
+
+static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+ return clk_prepare_enable(rp->clk);
+}
+
+static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+ clk_disable_unprepare(rp->clk);
+}
+
+static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+ int div, ret;
+
+ div = rcar_pwm_get_clock_division(rp, period_ns);
+ if (div < 0)
+ return div;
+
+ /* Let the core driver set pwm->period if disabled and duty_ns == 0 */
+ if (!test_bit(PWMF_ENABLED, &pwm->flags) && !duty_ns)
+ return 0;
+
+ rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
+
+ ret = rcar_pwm_set_counter(rp, div, duty_ns, period_ns);
+ if (!ret)
+ rcar_pwm_set_clock_control(rp, div);
+
+ /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
+ rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
+
+ return ret;
+}
+
+static int rcar_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+ u32 value;
+
+ /* Don't enable the PWM device if CYC0 or PH0 is 0 */
+ value = rcar_pwm_read(rp, RCAR_PWMCNT);
+ if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
+ (value & RCAR_PWMCNT_PH0_MASK) == 0)
+ return -EINVAL;
+
+ rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
+
+ return 0;
+}
+
+static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+ rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
+}
+
+static const struct pwm_ops rcar_pwm_ops = {
+ .request = rcar_pwm_request,
+ .free = rcar_pwm_free,
+ .config = rcar_pwm_config,
+ .enable = rcar_pwm_enable,
+ .disable = rcar_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int rcar_pwm_probe(struct platform_device *pdev)
+{
+ struct rcar_pwm_chip *rcar_pwm;
+ struct resource *res;
+ int ret;
+
+ rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
+ if (rcar_pwm == NULL)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rcar_pwm->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rcar_pwm->base))
+ return PTR_ERR(rcar_pwm->base);
+
+ rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(rcar_pwm->clk)) {
+ dev_err(&pdev->dev, "cannot get clock\n");
+ return PTR_ERR(rcar_pwm->clk);
+ }
+
+ platform_set_drvdata(pdev, rcar_pwm);
+
+ rcar_pwm->chip.dev = &pdev->dev;
+ rcar_pwm->chip.ops = &rcar_pwm_ops;
+ rcar_pwm->chip.base = -1;
+ rcar_pwm->chip.npwm = 1;
+
+ ret = pwmchip_add(&rcar_pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
+ return ret;
+ }
+
+ pm_runtime_enable(&pdev->dev);
+
+ return 0;
+}
+
+static int rcar_pwm_remove(struct platform_device *pdev)
+{
+ struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
+
+ pm_runtime_disable(&pdev->dev);
+
+ return pwmchip_remove(&rcar_pwm->chip);
+}
+
+static const struct of_device_id rcar_pwm_of_table[] = {
+ { .compatible = "renesas,pwm-rcar", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
+
+static struct platform_driver rcar_pwm_driver = {
+ .probe = rcar_pwm_probe,
+ .remove = rcar_pwm_remove,
+ .driver = {
+ .name = "pwm-rcar",
+ .of_match_table = of_match_ptr(rcar_pwm_of_table),
+ }
+};
+module_platform_driver(rcar_pwm_driver);
+
+MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
+MODULE_DESCRIPTION("Renesas PWM Timer Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:pwm-rcar");
