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authorThierry Reding <thierry.reding@avionic-design.de>2012-01-02 21:22:38 +0100
committerThierry Reding <thierry.reding@avionic-design.de>2012-07-02 21:39:00 +0200
commit17b2b4780f879a559b8dc96c170dd6df98fe9ab3 (patch)
treea7e7915adf0a94828811a72b8ab35e83fcdbabfd /drivers/pwm/pwm-pxa.c
parenta4315e3c11f97ea0fa602184fa310161309657df (diff)
downloadlinux-stericsson-17b2b4780f879a559b8dc96c170dd6df98fe9ab3.tar.gz
pwm: Move PXA PWM driver to PWM framework
This commit moves the PXA PWM driver to the drivers/pwm subdirectory and converts it to use the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'drivers/pwm/pwm-pxa.c')
-rw-r--r--drivers/pwm/pwm-pxa.c248
1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
new file mode 100644
index 000000000000..d5c6ce513e29
--- /dev/null
+++ b/drivers/pwm/pwm-pxa.c
@@ -0,0 +1,248 @@
+/*
+ * linux/arch/arm/mach-pxa/pwm.c
+ *
+ * simple driver for PWM (Pulse Width Modulator) controller
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 2008-02-13 initial version
+ * eric miao <eric.miao@marvell.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+
+#include <asm/div64.h>
+
+#define HAS_SECONDARY_PWM 0x10
+#define PWM_ID_BASE(d) ((d) & 0xf)
+
+static const struct platform_device_id pwm_id_table[] = {
+ /* PWM has_secondary_pwm? */
+ { "pxa25x-pwm", 0 },
+ { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
+ { "pxa168-pwm", 1 },
+ { "pxa910-pwm", 1 },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, pwm_id_table);
+
+/* PWM registers and bits definitions */
+#define PWMCR (0x00)
+#define PWMDCR (0x04)
+#define PWMPCR (0x08)
+
+#define PWMCR_SD (1 << 6)
+#define PWMDCR_FD (1 << 10)
+
+struct pxa_pwm_chip {
+ struct pwm_chip chip;
+ struct device *dev;
+
+ struct clk *clk;
+ int clk_enabled;
+ void __iomem *mmio_base;
+};
+
+static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct pxa_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ */
+static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+ unsigned long long c;
+ unsigned long period_cycles, prescale, pv, dc;
+ unsigned long offset;
+ int rc;
+
+ if (period_ns == 0 || duty_ns > period_ns)
+ return -EINVAL;
+
+ offset = pwm->hwpwm ? 0x10 : 0;
+
+ c = clk_get_rate(pc->clk);
+ c = c * period_ns;
+ do_div(c, 1000000000);
+ period_cycles = c;
+
+ if (period_cycles < 1)
+ period_cycles = 1;
+ prescale = (period_cycles - 1) / 1024;
+ pv = period_cycles / (prescale + 1) - 1;
+
+ if (prescale > 63)
+ return -EINVAL;
+
+ if (duty_ns == period_ns)
+ dc = PWMDCR_FD;
+ else
+ dc = (pv + 1) * duty_ns / period_ns;
+
+ /* NOTE: the clock to PWM has to be enabled first
+ * before writing to the registers
+ */
+ rc = clk_prepare_enable(pc->clk);
+ if (rc < 0)
+ return rc;
+
+ writel(prescale, pc->mmio_base + offset + PWMCR);
+ writel(dc, pc->mmio_base + offset + PWMDCR);
+ writel(pv, pc->mmio_base + offset + PWMPCR);
+
+ clk_disable_unprepare(pc->clk);
+ return 0;
+}
+
+static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+ int rc = 0;
+
+ if (!pc->clk_enabled) {
+ rc = clk_prepare_enable(pc->clk);
+ if (!rc)
+ pc->clk_enabled++;
+ }
+ return rc;
+}
+
+static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+
+ if (pc->clk_enabled) {
+ clk_disable_unprepare(pc->clk);
+ pc->clk_enabled--;
+ }
+}
+
+static struct pwm_ops pxa_pwm_ops = {
+ .config = pxa_pwm_config,
+ .enable = pxa_pwm_enable,
+ .disable = pxa_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int __devinit pwm_probe(struct platform_device *pdev)
+{
+ const struct platform_device_id *id = platform_get_device_id(pdev);
+ struct pxa_pwm_chip *pwm;
+ struct resource *r;
+ int ret = 0;
+
+ pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
+ if (pwm == NULL) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ pwm->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk)) {
+ ret = PTR_ERR(pwm->clk);
+ goto err_free;
+ }
+ pwm->clk_enabled = 0;
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &pxa_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (r == NULL) {
+ dev_err(&pdev->dev, "no memory resource defined\n");
+ ret = -ENODEV;
+ goto err_free_clk;
+ }
+
+ r = request_mem_region(r->start, resource_size(r), pdev->name);
+ if (r == NULL) {
+ dev_err(&pdev->dev, "failed to request memory resource\n");
+ ret = -EBUSY;
+ goto err_free_clk;
+ }
+
+ pwm->mmio_base = ioremap(r->start, resource_size(r));
+ if (pwm->mmio_base == NULL) {
+ dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ ret = -ENODEV;
+ goto err_free_mem;
+ }
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+ return 0;
+
+err_free_mem:
+ release_mem_region(r->start, resource_size(r));
+err_free_clk:
+ clk_put(pwm->clk);
+err_free:
+ kfree(pwm);
+ return ret;
+}
+
+static int __devexit pwm_remove(struct platform_device *pdev)
+{
+ struct pxa_pwm_chip *chip;
+ struct resource *r;
+
+ chip = platform_get_drvdata(pdev);
+ if (chip == NULL)
+ return -ENODEV;
+
+ pwmchip_remove(&chip->chip);
+
+ iounmap(chip->mmio_base);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ release_mem_region(r->start, resource_size(r));
+
+ clk_put(chip->clk);
+ kfree(chip);
+ return 0;
+}
+
+static struct platform_driver pwm_driver = {
+ .driver = {
+ .name = "pxa25x-pwm",
+ .owner = THIS_MODULE,
+ },
+ .probe = pwm_probe,
+ .remove = __devexit_p(pwm_remove),
+ .id_table = pwm_id_table,
+};
+
+static int __init pwm_init(void)
+{
+ return platform_driver_register(&pwm_driver);
+}
+arch_initcall(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+ platform_driver_unregister(&pwm_driver);
+}
+module_exit(pwm_exit);
+
+MODULE_LICENSE("GPL v2");