[PATCH 2/2] pwm: Add a i.MX23/28 pwm driver
From: Lothar Waßmann <hidden>
Date: 2011-06-28 10:50:21
Also in:
lkml
Hi, just some nitpicks... Sascha Hauer writes:
quoted hunk ↗ jump to hunk
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> --- drivers/pwm/mxs-pwm.c | 275 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 275 insertions(+), 0 deletions(-) create mode 100644 drivers/pwm/mxs-pwm.cdiff --git a/drivers/pwm/mxs-pwm.c b/drivers/pwm/mxs-pwm.c new file mode 100644 index 0000000..052cb0c --- /dev/null +++ b/drivers/pwm/mxs-pwm.c@@ -0,0 +1,275 @@ +/* + * Copyright (C) 2011 Pengutronix + * Sascha Hauer <s.hauer@pengutronix.de> + * + * 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. + * + * Derived from pxa PWM driver by 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/delay.h> +#include <linux/io.h> +#include <linux/pwm.h> +#include <mach/hardware.h> +#include <mach/mxs.h> +#include <mach/mx23.h> +#include <mach/mx28.h> +#include <asm/div64.h> + +struct mxs_pwm_device { + struct device *dev; + + struct clk *clk; + + int enabled; + void __iomem *mmio_base; + + unsigned int pwm_id; + + u32 val_active; + u32 val_period; + int period_us; + struct pwm_chip chip; +}; + +/* common register space */ +static void __iomem *pwm_base_common; +#define REG_PWM_CTRL 0x0 +#define PWM_SFTRST (1 << 31) +#define PWM_CLKGATE (1 << 30) +#define PWM_ENABLE(p) (1 << (p)) + +/* per pwm register space */ +#define REG_ACTIVE 0x0 +#define REG_PERIOD 0x10 + +#define PERIOD_PERIOD(p) ((p) & 0xffff) +#define PERIOD_ACTIVE_HIGH (3 << 16) +#define PERIOD_INACTIVE_LOW (2 << 18) +#define PERIOD_CDIV(div) (((div) & 0x7) << 20) +
[...]
+static int __devinit mxs_pwm_probe(struct platform_device *pdev)
+{
+ struct mxs_pwm_device *pwm;
+ struct resource *r;
+ int ret = 0;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(struct mxs_pwm_device), 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)) {Why an empty line here, but not in other similar places?
+ ret = PTR_ERR(pwm->clk); + goto err_free; + } + + pwm->chip.ops = &mxs_pwm_ops; + + pwm->enabled = 0;
is already 0 due to kzalloc().
+
+ pwm->chip.pwm_id = pdev->id;
+ pwm->chip.owner = THIS_MODULE;
+
+ 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;-ENOMEM?.
+ if (ret)
+ goto err_free_mem;
+
+ 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 mxs_pwm_remove(struct platform_device *pdev)
+{
+ struct mxs_pwm_device *pwm;
+ struct resource *r;
+ int ret;
+
+ pwm = platform_get_drvdata(pdev);
+
+ ret = pwmchip_remove(&pwm->chip);
+ if (ret)
+ return ret;
+
+ iounmap(pwm->mmio_base);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ release_mem_region(r->start, resource_size(r));
+
+ clk_put(pwm->clk);
+
+ return 0;
+}
+
+static struct platform_driver mxs_pwm_driver = {
+ .driver = {
+ .name = "mxs-pwm",
+ },
+ .probe = mxs_pwm_probe,
+ .remove = __devexit_p(mxs_pwm_remove),
+};
+
+static int __init mxs_pwm_init(void)
+{
+ if (cpu_is_mx28())
+ pwm_base_common = MX28_IO_ADDRESS(MX28_PWM_BASE_ADDR);
+ else
+ pwm_base_common = MX23_IO_ADDRESS(MX23_PWM_BASE_ADDR);
+
+ __mxs_clrl(PWM_SFTRST | PWM_CLKGATE, pwm_base_common + REG_PWM_CTRL);
+Shouldn't CLKGATE be set again in the remove() function? Lothar Wa?mann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstra?e 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Gesch?ftsf?hrer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info at karo-electronics.de ___________________________________________________________