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authorLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 09:22:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 09:22:37 -0700
commit9ec97169e7d6afe2f8206d694d1411fb3bb49853 (patch)
tree9d24c8cd440a312f96b70db5cdaaef1136787003 /drivers/pwm/pwm-tiecap.c
parenta410963ba4c0c768302f0298e258b1ee940e8316 (diff)
parent19891b20e7c275feb92d669f4b1879861f7e8c25 (diff)
Merge branch 'for-3.6' of git://gitorious.org/linux-pwm/linux-pwm
Pull PWM subsystem from Thierry Reding: "The new PWM subsystem aims at collecting all implementations of the legacy PWM API and to eventually replace it completely. The subsystem has been in development for over half a year now and many drivers have already been converted. It has been in linux-next for a couple of weeks and there have been no major issues so I think it is ready for inclusion in your tree." Arnd Bergmann <arnd@arndb.de>: "Very much Ack on the new subsystem. It uses the interface declarations as the previously separate pwm drivers, so nothing changes for now in the drivers using it, although it enables us to change those more easily in the future if we want to. This work is also one of the missing pieces that are required to eventually build ARM kernels for multiple platforms, which is currently prohibited (amongs other things) by the fact that you cannot have more than one driver exporting the pwm functions." Tested-and-acked-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Philip, Avinash <avinashphilip@ti.com> # TI's AM33xx platforms Acked-By: Alexandre Pereira da Silva <aletes.xgr@gmail.com> # LPC32XX Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Sachin Kamat <sachin.kamat@linaro.org> Fix up trivial conflicts with other cleanups and DT updates. * 'for-3.6' of git://gitorious.org/linux-pwm/linux-pwm: (36 commits) pwm: pwm-tiehrpwm: PWM driver support for EHRPWM pwm: pwm-tiecap: PWM driver support for ECAP APWM pwm: fix used-uninitialized warning in pwm_get() pwm: add lpc32xx PWM support pwm_backlight: pass correct brightness to callback pwm: Use pr_* functions in pwm-samsung.c file pwm: Convert pwm-samsung to use devm_* APIs pwm: Convert pwm-tegra to use devm_clk_get() pwm: pwm-mxs: Return proper error if pwmchip_remove() fails pwm: pwm-bfin: Return proper error if pwmchip_remove() fails pwm: pxa: Propagate pwmchip_remove() error pwm: Convert pwm-pxa to use devm_* APIs pwm: Convert pwm-vt8500 to use devm_* APIs pwm: Convert pwm-imx to use devm_* APIs pwm: Conflict with legacy PWM API pwm: pwm-mxs: add pinctrl support pwm: pwm-mxs: use devm_* managed functions pwm: pwm-mxs: use global reset function stmp_reset_block pwm: pwm-mxs: encode soc name in compatible string pwm: Take over maintainership of the PWM subsystem ...
Diffstat (limited to 'drivers/pwm/pwm-tiecap.c')
-rw-r--r--drivers/pwm/pwm-tiecap.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
new file mode 100644
index 00000000000..3c2ad284ee3
--- /dev/null
+++ b/drivers/pwm/pwm-tiecap.c
@@ -0,0 +1,232 @@
+/*
+ * ECAP PWM driver
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+
+/* ECAP registers and bits definitions */
+#define CAP1 0x08
+#define CAP2 0x0C
+#define CAP3 0x10
+#define CAP4 0x14
+#define ECCTL2 0x2A
+#define ECCTL2_APWM_MODE BIT(9)
+#define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
+#define ECCTL2_TSCTR_FREERUN BIT(4)
+
+struct ecap_pwm_chip {
+ struct pwm_chip chip;
+ unsigned int clk_rate;
+ void __iomem *mmio_base;
+};
+
+static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct ecap_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
+ * duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
+ */
+static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned long long c;
+ unsigned long period_cycles, duty_cycles;
+ unsigned int reg_val;
+
+ if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
+ return -ERANGE;
+
+ c = pc->clk_rate;
+ c = c * period_ns;
+ do_div(c, NSEC_PER_SEC);
+ period_cycles = (unsigned long)c;
+
+ if (period_cycles < 1) {
+ period_cycles = 1;
+ duty_cycles = 1;
+ } else {
+ c = pc->clk_rate;
+ c = c * duty_ns;
+ do_div(c, NSEC_PER_SEC);
+ duty_cycles = (unsigned long)c;
+ }
+
+ pm_runtime_get_sync(pc->chip.dev);
+
+ reg_val = readw(pc->mmio_base + ECCTL2);
+
+ /* Configure APWM mode & disable sync option */
+ reg_val |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
+
+ writew(reg_val, pc->mmio_base + ECCTL2);
+
+ if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+ /* Update active registers if not running */
+ writel(duty_cycles, pc->mmio_base + CAP2);
+ writel(period_cycles, pc->mmio_base + CAP1);
+ } else {
+ /*
+ * Update shadow registers to configure period and
+ * compare values. This helps current PWM period to
+ * complete on reconfiguring
+ */
+ writel(duty_cycles, pc->mmio_base + CAP4);
+ writel(period_cycles, pc->mmio_base + CAP3);
+ }
+
+ pm_runtime_put_sync(pc->chip.dev);
+ return 0;
+}
+
+static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned int reg_val;
+
+ /* Leave clock enabled on enabling PWM */
+ pm_runtime_get_sync(pc->chip.dev);
+
+ /*
+ * Enable 'Free run Time stamp counter mode' to start counter
+ * and 'APWM mode' to enable APWM output
+ */
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ reg_val |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
+ writew(reg_val, pc->mmio_base + ECCTL2);
+ return 0;
+}
+
+static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned int reg_val;
+
+ /*
+ * Disable 'Free run Time stamp counter mode' to stop counter
+ * and 'APWM mode' to put APWM output to low
+ */
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ reg_val &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
+ writew(reg_val, pc->mmio_base + ECCTL2);
+
+ /* Disable clock on PWM disable */
+ pm_runtime_put_sync(pc->chip.dev);
+}
+
+static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+ dev_warn(chip->dev, "Removing PWM device without disabling\n");
+ pm_runtime_put_sync(chip->dev);
+ }
+}
+
+static const struct pwm_ops ecap_pwm_ops = {
+ .free = ecap_pwm_free,
+ .config = ecap_pwm_config,
+ .enable = ecap_pwm_enable,
+ .disable = ecap_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int __devinit ecap_pwm_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct resource *r;
+ struct clk *clk;
+ struct ecap_pwm_chip *pc;
+
+ pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
+ if (!pc) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ clk = devm_clk_get(&pdev->dev, "fck");
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "failed to get clock\n");
+ return PTR_ERR(clk);
+ }
+
+ pc->clk_rate = clk_get_rate(clk);
+ if (!pc->clk_rate) {
+ dev_err(&pdev->dev, "failed to get clock rate\n");
+ return -EINVAL;
+ }
+
+ pc->chip.dev = &pdev->dev;
+ pc->chip.ops = &ecap_pwm_ops;
+ pc->chip.base = -1;
+ pc->chip.npwm = 1;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "no memory resource defined\n");
+ return -ENODEV;
+ }
+
+ pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
+ if (!pc->mmio_base) {
+ dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ ret = pwmchip_add(&pc->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+ return ret;
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ platform_set_drvdata(pdev, pc);
+ return 0;
+}
+
+static int __devexit ecap_pwm_remove(struct platform_device *pdev)
+{
+ struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
+
+ pm_runtime_put_sync(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+ return pwmchip_remove(&pc->chip);
+}
+
+static struct platform_driver ecap_pwm_driver = {
+ .driver = {
+ .name = "ecap",
+ },
+ .probe = ecap_pwm_probe,
+ .remove = __devexit_p(ecap_pwm_remove),
+};
+
+module_platform_driver(ecap_pwm_driver);
+
+MODULE_DESCRIPTION("ECAP PWM driver");
+MODULE_AUTHOR("Texas Instruments");
+MODULE_LICENSE("GPL");