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authorIngo Molnar <mingo@kernel.org>2012-08-21 11:27:00 +0200
committerIngo Molnar <mingo@kernel.org>2012-08-21 11:27:00 +0200
commitbcada3d4b8c96b8792c2306f363992ca5ab9da42 (patch)
treee420679a5db6ea4e1694eef57f9abb6acac8d4d3 /drivers/pwm/pwm-tegra.c
parent26198c21d1b286a084fe5d514a30bc7e6c712a34 (diff)
parent000078bc3ee69efb1124b8478c7527389a826074 (diff)
Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: * Fix include order for bison/flex-generated C files, from Ben Hutchings * Build fixes and documentation corrections from David Ahern * Group parsing support, from Jiri Olsa * UI/gtk refactorings and improvements from Namhyung Kim * NULL deref fix for perf script, from Namhyung Kim * Assorted cleanups from Robert Richter * Let O= makes handle relative paths, from Steven Rostedt * perf script python fixes, from Feng Tang. * Improve 'perf lock' error message when the needed tracepoints are not present, from David Ahern. * Initial bash completion support, from Frederic Weisbecker * Allow building without libelf, from Namhyung Kim. * Support DWARF CFI based unwind to have callchains when %bp based unwinding is not possible, from Jiri Olsa. * Symbol resolution fixes, while fixing support PPC64 files with an .opt ELF section was the end goal, several fixes for code that handles all architectures and cleanups are included, from Cody Schafer. * Add a description for the JIT interface, from Andi Kleen. * Assorted fixes for Documentation and build in 32 bit, from Robert Richter * Add support for non-tracepoint events in perf script python, from Feng Tang * Cache the libtraceevent event_format associated to each evsel early, so that we avoid relookups, i.e. calling pevent_find_event repeatedly when processing tracepoint events. [ This is to reduce the surface contact with libtraceevents and make clear what is that the perf tools needs from that lib: so far parsing the common and per event fields. ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/pwm/pwm-tegra.c')
-rw-r--r--drivers/pwm/pwm-tegra.c261
1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
new file mode 100644
index 00000000000..02ce18d5e49
--- /dev/null
+++ b/drivers/pwm/pwm-tegra.c
@@ -0,0 +1,261 @@
+/*
+ * drivers/pwm/pwm-tegra.c
+ *
+ * Tegra pulse-width-modulation controller driver
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ * Based on arch/arm/plat-mxc/pwm.c by Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pwm.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define PWM_ENABLE (1 << 31)
+#define PWM_DUTY_WIDTH 8
+#define PWM_DUTY_SHIFT 16
+#define PWM_SCALE_WIDTH 13
+#define PWM_SCALE_SHIFT 0
+
+#define NUM_PWM 4
+
+struct tegra_pwm_chip {
+ struct pwm_chip chip;
+ struct device *dev;
+
+ struct clk *clk;
+
+ void __iomem *mmio_base;
+};
+
+static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct tegra_pwm_chip, chip);
+}
+
+static inline u32 pwm_readl(struct tegra_pwm_chip *chip, unsigned int num)
+{
+ return readl(chip->mmio_base + (num << 4));
+}
+
+static inline void pwm_writel(struct tegra_pwm_chip *chip, unsigned int num,
+ unsigned long val)
+{
+ writel(val, chip->mmio_base + (num << 4));
+}
+
+static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
+ unsigned long long c;
+ unsigned long rate, hz;
+ u32 val = 0;
+ int err;
+
+ /*
+ * Convert from duty_ns / period_ns to a fixed number of duty ticks
+ * per (1 << PWM_DUTY_WIDTH) cycles and make sure to round to the
+ * nearest integer during division.
+ */
+ c = duty_ns * ((1 << PWM_DUTY_WIDTH) - 1) + period_ns / 2;
+ do_div(c, period_ns);
+
+ val = (u32)c << PWM_DUTY_SHIFT;
+
+ /*
+ * Compute the prescaler value for which (1 << PWM_DUTY_WIDTH)
+ * cycles at the PWM clock rate will take period_ns nanoseconds.
+ */
+ rate = clk_get_rate(pc->clk) >> PWM_DUTY_WIDTH;
+ hz = 1000000000ul / period_ns;
+
+ rate = (rate + (hz / 2)) / hz;
+
+ /*
+ * Since the actual PWM divider is the register's frequency divider
+ * field minus 1, we need to decrement to get the correct value to
+ * write to the register.
+ */
+ if (rate > 0)
+ rate--;
+
+ /*
+ * Make sure that the rate will fit in the register's frequency
+ * divider field.
+ */
+ if (rate >> PWM_SCALE_WIDTH)
+ return -EINVAL;
+
+ val |= rate << PWM_SCALE_SHIFT;
+
+ /*
+ * If the PWM channel is disabled, make sure to turn on the clock
+ * before writing the register. Otherwise, keep it enabled.
+ */
+ if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+ err = clk_prepare_enable(pc->clk);
+ if (err < 0)
+ return err;
+ } else
+ val |= PWM_ENABLE;
+
+ pwm_writel(pc, pwm->hwpwm, val);
+
+ /*
+ * If the PWM is not enabled, turn the clock off again to save power.
+ */
+ if (!test_bit(PWMF_ENABLED, &pwm->flags))
+ clk_disable_unprepare(pc->clk);
+
+ return 0;
+}
+
+static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
+ int rc = 0;
+ u32 val;
+
+ rc = clk_prepare_enable(pc->clk);
+ if (rc < 0)
+ return rc;
+
+ val = pwm_readl(pc, pwm->hwpwm);
+ val |= PWM_ENABLE;
+ pwm_writel(pc, pwm->hwpwm, val);
+
+ return 0;
+}
+
+static void tegra_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
+ u32 val;
+
+ val = pwm_readl(pc, pwm->hwpwm);
+ val &= ~PWM_ENABLE;
+ pwm_writel(pc, pwm->hwpwm, val);
+
+ clk_disable_unprepare(pc->clk);
+}
+
+static const struct pwm_ops tegra_pwm_ops = {
+ .config = tegra_pwm_config,
+ .enable = tegra_pwm_enable,
+ .disable = tegra_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int tegra_pwm_probe(struct platform_device *pdev)
+{
+ struct tegra_pwm_chip *pwm;
+ struct resource *r;
+ int ret;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ pwm->dev = &pdev->dev;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "no memory resources defined\n");
+ return -ENODEV;
+ }
+
+ pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
+ if (!pwm->mmio_base) {
+ dev_err(&pdev->dev, "failed to ioremap() region\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+
+ pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk))
+ return PTR_ERR(pwm->clk);
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &tegra_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = NUM_PWM;
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int __devexit tegra_pwm_remove(struct platform_device *pdev)
+{
+ struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
+ int i;
+
+ if (WARN_ON(!pc))
+ return -ENODEV;
+
+ for (i = 0; i < NUM_PWM; i++) {
+ struct pwm_device *pwm = &pc->chip.pwms[i];
+
+ if (!test_bit(PWMF_ENABLED, &pwm->flags))
+ if (clk_prepare_enable(pc->clk) < 0)
+ continue;
+
+ pwm_writel(pc, i, 0);
+
+ clk_disable_unprepare(pc->clk);
+ }
+
+ return pwmchip_remove(&pc->chip);
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id tegra_pwm_of_match[] = {
+ { .compatible = "nvidia,tegra20-pwm" },
+ { .compatible = "nvidia,tegra30-pwm" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, tegra_pwm_of_match);
+#endif
+
+static struct platform_driver tegra_pwm_driver = {
+ .driver = {
+ .name = "tegra-pwm",
+ .of_match_table = of_match_ptr(tegra_pwm_of_match),
+ },
+ .probe = tegra_pwm_probe,
+ .remove = __devexit_p(tegra_pwm_remove),
+};
+
+module_platform_driver(tegra_pwm_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("NVIDIA Corporation");
+MODULE_ALIAS("platform:tegra-pwm");