diff options
author | Ingo Molnar <mingo@kernel.org> | 2012-08-21 11:27:00 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2012-08-21 11:27:00 +0200 |
commit | bcada3d4b8c96b8792c2306f363992ca5ab9da42 (patch) | |
tree | e420679a5db6ea4e1694eef57f9abb6acac8d4d3 /drivers/pwm/pwm-imx.c | |
parent | 26198c21d1b286a084fe5d514a30bc7e6c712a34 (diff) | |
parent | 000078bc3ee69efb1124b8478c7527389a826074 (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-imx.c')
-rw-r--r-- | drivers/pwm/pwm-imx.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c new file mode 100644 index 00000000000..2a0b3533397 --- /dev/null +++ b/drivers/pwm/pwm-imx.c @@ -0,0 +1,230 @@ +/* + * 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/io.h> +#include <linux/pwm.h> +#include <mach/hardware.h> + + +/* i.MX1 and i.MX21 share the same PWM function block: */ + +#define MX1_PWMC 0x00 /* PWM Control Register */ +#define MX1_PWMS 0x04 /* PWM Sample Register */ +#define MX1_PWMP 0x08 /* PWM Period Register */ + + +/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */ + +#define MX3_PWMCR 0x00 /* PWM Control Register */ +#define MX3_PWMSAR 0x0C /* PWM Sample Register */ +#define MX3_PWMPR 0x10 /* PWM Period Register */ +#define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4) +#define MX3_PWMCR_DOZEEN (1 << 24) +#define MX3_PWMCR_WAITEN (1 << 23) +#define MX3_PWMCR_DBGEN (1 << 22) +#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16) +#define MX3_PWMCR_CLKSRC_IPG (1 << 16) +#define MX3_PWMCR_EN (1 << 0) + +struct imx_chip { + struct clk *clk; + + int clk_enabled; + void __iomem *mmio_base; + + struct pwm_chip chip; +}; + +#define to_imx_chip(chip) container_of(chip, struct imx_chip, chip) + +static int imx_pwm_config(struct pwm_chip *chip, + struct pwm_device *pwm, int duty_ns, int period_ns) +{ + struct imx_chip *imx = to_imx_chip(chip); + + if (!(cpu_is_mx1() || cpu_is_mx21())) { + unsigned long long c; + unsigned long period_cycles, duty_cycles, prescale; + u32 cr; + + c = clk_get_rate(imx->clk); + c = c * period_ns; + do_div(c, 1000000000); + period_cycles = c; + + prescale = period_cycles / 0x10000 + 1; + + period_cycles /= prescale; + c = (unsigned long long)period_cycles * duty_ns; + do_div(c, period_ns); + duty_cycles = c; + + /* + * according to imx pwm RM, the real period value should be + * PERIOD value in PWMPR plus 2. + */ + if (period_cycles > 2) + period_cycles -= 2; + else + period_cycles = 0; + + writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); + writel(period_cycles, imx->mmio_base + MX3_PWMPR); + + cr = MX3_PWMCR_PRESCALER(prescale) | + MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | + MX3_PWMCR_DBGEN | MX3_PWMCR_EN; + + if (cpu_is_mx25()) + cr |= MX3_PWMCR_CLKSRC_IPG; + else + cr |= MX3_PWMCR_CLKSRC_IPG_HIGH; + + writel(cr, imx->mmio_base + MX3_PWMCR); + } else if (cpu_is_mx1() || cpu_is_mx21()) { + /* The PWM subsystem allows for exact frequencies. However, + * I cannot connect a scope on my device to the PWM line and + * thus cannot provide the program the PWM controller + * exactly. Instead, I'm relying on the fact that the + * Bootloader (u-boot or WinCE+haret) has programmed the PWM + * function group already. So I'll just modify the PWM sample + * register to follow the ratio of duty_ns vs. period_ns + * accordingly. + * + * This is good enough for programming the brightness of + * the LCD backlight. + * + * The real implementation would divide PERCLK[0] first by + * both the prescaler (/1 .. /128) and then by CLKSEL + * (/2 .. /16). + */ + u32 max = readl(imx->mmio_base + MX1_PWMP); + u32 p = max * duty_ns / period_ns; + writel(max - p, imx->mmio_base + MX1_PWMS); + } else { + BUG(); + } + + return 0; +} + +static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct imx_chip *imx = to_imx_chip(chip); + int rc = 0; + + if (!imx->clk_enabled) { + rc = clk_prepare_enable(imx->clk); + if (!rc) + imx->clk_enabled = 1; + } + return rc; +} + +static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct imx_chip *imx = to_imx_chip(chip); + + writel(0, imx->mmio_base + MX3_PWMCR); + + if (imx->clk_enabled) { + clk_disable_unprepare(imx->clk); + imx->clk_enabled = 0; + } +} + +static struct pwm_ops imx_pwm_ops = { + .enable = imx_pwm_enable, + .disable = imx_pwm_disable, + .config = imx_pwm_config, + .owner = THIS_MODULE, +}; + +static int __devinit imx_pwm_probe(struct platform_device *pdev) +{ + struct imx_chip *imx; + struct resource *r; + int ret = 0; + + imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL); + if (imx == NULL) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + imx->clk = devm_clk_get(&pdev->dev, "pwm"); + + if (IS_ERR(imx->clk)) + return PTR_ERR(imx->clk); + + imx->chip.ops = &imx_pwm_ops; + imx->chip.dev = &pdev->dev; + imx->chip.base = -1; + imx->chip.npwm = 1; + + imx->clk_enabled = 0; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + dev_err(&pdev->dev, "no memory resource defined\n"); + return -ENODEV; + } + + imx->mmio_base = devm_request_and_ioremap(&pdev->dev, r); + if (imx->mmio_base == NULL) + return -EADDRNOTAVAIL; + + ret = pwmchip_add(&imx->chip); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, imx); + return 0; +} + +static int __devexit imx_pwm_remove(struct platform_device *pdev) +{ + struct imx_chip *imx; + + imx = platform_get_drvdata(pdev); + if (imx == NULL) + return -ENODEV; + + return pwmchip_remove(&imx->chip); +} + +static struct platform_driver imx_pwm_driver = { + .driver = { + .name = "mxc_pwm", + }, + .probe = imx_pwm_probe, + .remove = __devexit_p(imx_pwm_remove), +}; + +static int __init imx_pwm_init(void) +{ + return platform_driver_register(&imx_pwm_driver); +} +arch_initcall(imx_pwm_init); + +static void __exit imx_pwm_exit(void) +{ + platform_driver_unregister(&imx_pwm_driver); +} +module_exit(imx_pwm_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); |