summaryrefslogtreecommitdiff
path: root/drivers
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 03:14:09 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 03:14:09 +0300
commitb615d3d406ead1157c6b846c417b71a3b6600776 (patch)
tree557d312251c6d4fc5abc1ec8ae24b987f175c4fe /drivers
parented7d6bc23b6dd8f5272431ce930c84d1e537be49 (diff)
parent922201d129c8f9d0c3207dca90ea6ffd8e2242f0 (diff)
downloadlinux-b615d3d406ead1157c6b846c417b71a3b6600776.tar.xz
Merge tag 'pwm/for-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding: "No new drivers this time around, but a handful of cleanups and fixes" * tag 'pwm/for-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: pwm: omap-dmtimer: Add debug message for effective period and duty cycle pwm: omap-dmtimer: Round load and match values rather than truncate pwm: omap-dmtimer: Add sanity checking for load and match values pwm: omap-dmtimer: Fix inaccurate period and duty cycle calculations pwm: brcmstb: Fix check of devm_ioremap_resource() return code pwm: rcar: Depend on ARCH_RENESAS instead of ARCH_SHMOBILE pwm: lpc18xx-sct: Test clock rate to avoid division by 0 pwm: img: Test clock rate to avoid division by 0
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pwm/Kconfig2
-rw-r--r--drivers/pwm/pwm-brcmstb.c4
-rw-r--r--drivers/pwm/pwm-img.c5
-rw-r--r--drivers/pwm/pwm-lpc18xx-sct.c5
-rw-r--r--drivers/pwm/pwm-omap-dmtimer.c74
5 files changed, 71 insertions, 19 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 8cf0dae78555..c182efc62c7b 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -316,7 +316,7 @@ config PWM_RCAR
config PWM_RENESAS_TPU
tristate "Renesas TPU PWM support"
- depends on ARCH_SHMOBILE || COMPILE_TEST
+ depends on ARCH_RENESAS || COMPILE_TEST
depends on HAS_IOMEM
help
This driver exposes the Timer Pulse Unit (TPU) PWM controller found
diff --git a/drivers/pwm/pwm-brcmstb.c b/drivers/pwm/pwm-brcmstb.c
index 423ce087cd9c..5d5adee16886 100644
--- a/drivers/pwm/pwm-brcmstb.c
+++ b/drivers/pwm/pwm-brcmstb.c
@@ -274,8 +274,8 @@ static int brcmstb_pwm_probe(struct platform_device *pdev)
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
p->base = devm_ioremap_resource(&pdev->dev, res);
- if (!p->base) {
- ret = -ENOMEM;
+ if (IS_ERR(p->base)) {
+ ret = PTR_ERR(p->base);
goto out_clk;
}
diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
index 8a029f9bc18c..2fb30deee345 100644
--- a/drivers/pwm/pwm-img.c
+++ b/drivers/pwm/pwm-img.c
@@ -237,6 +237,11 @@ static int img_pwm_probe(struct platform_device *pdev)
}
clk_rate = clk_get_rate(pwm->pwm_clk);
+ if (!clk_rate) {
+ dev_err(&pdev->dev, "pwm clock has no frequency\n");
+ ret = -EINVAL;
+ goto disable_pwmclk;
+ }
/* The maximum input clock divider is 512 */
val = (u64)NSEC_PER_SEC * 512 * pwm->data->max_timebase;
diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
index 9163085101bc..9861fed4e67d 100644
--- a/drivers/pwm/pwm-lpc18xx-sct.c
+++ b/drivers/pwm/pwm-lpc18xx-sct.c
@@ -360,6 +360,11 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
}
lpc18xx_pwm->clk_rate = clk_get_rate(lpc18xx_pwm->pwm_clk);
+ if (!lpc18xx_pwm->clk_rate) {
+ dev_err(&pdev->dev, "pwm clock has no frequency\n");
+ ret = -EINVAL;
+ goto disable_pwmclk;
+ }
mutex_init(&lpc18xx_pwm->res_lock);
mutex_init(&lpc18xx_pwm->period_lock);
diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index 826634ec0d5c..b7e6ecba7d5c 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -31,6 +31,7 @@
#include <linux/time.h>
#define DM_TIMER_LOAD_MIN 0xfffffffe
+#define DM_TIMER_MAX 0xffffffff
struct pwm_omap_dmtimer_chip {
struct pwm_chip chip;
@@ -46,13 +47,9 @@ to_pwm_omap_dmtimer_chip(struct pwm_chip *chip)
return container_of(chip, struct pwm_omap_dmtimer_chip, chip);
}
-static int pwm_omap_dmtimer_calc_value(unsigned long clk_rate, int ns)
+static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns)
{
- u64 c = (u64)clk_rate * ns;
-
- do_div(c, NSEC_PER_SEC);
-
- return DM_TIMER_LOAD_MIN - c;
+ return DIV_ROUND_CLOSEST_ULL((u64)clk_rate * ns, NSEC_PER_SEC);
}
static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
@@ -99,12 +96,14 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
int duty_ns, int period_ns)
{
struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
- int load_value, match_value;
+ u32 period_cycles, duty_cycles;
+ u32 load_value, match_value;
struct clk *fclk;
unsigned long clk_rate;
bool timer_active;
- dev_dbg(chip->dev, "duty cycle: %d, period %d\n", duty_ns, period_ns);
+ dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",
+ duty_ns, period_ns);
mutex_lock(&omap->mutex);
if (duty_ns == pwm_get_duty_cycle(pwm) &&
@@ -117,15 +116,13 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
fclk = omap->pdata->get_fclk(omap->dm_timer);
if (!fclk) {
dev_err(chip->dev, "invalid pmtimer fclk\n");
- mutex_unlock(&omap->mutex);
- return -EINVAL;
+ goto err_einval;
}
clk_rate = clk_get_rate(fclk);
if (!clk_rate) {
dev_err(chip->dev, "invalid pmtimer fclk rate\n");
- mutex_unlock(&omap->mutex);
- return -EINVAL;
+ goto err_einval;
}
dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);
@@ -133,11 +130,51 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
/*
* Calculate the appropriate load and match values based on the
* specified period and duty cycle. The load value determines the
- * cycle time and the match value determines the duty cycle.
+ * period time and the match value determines the duty time.
+ *
+ * The period lasts for (DM_TIMER_MAX-load_value+1) clock cycles.
+ * Similarly, the active time lasts (match_value-load_value+1) cycles.
+ * The non-active time is the remainder: (DM_TIMER_MAX-match_value)
+ * clock cycles.
+ *
+ * NOTE: It is required that: load_value <= match_value < DM_TIMER_MAX
+ *
+ * References:
+ * OMAP4430/60/70 TRM sections 22.2.4.10 and 22.2.4.11
+ * AM335x Sitara TRM sections 20.1.3.5 and 20.1.3.6
*/
- load_value = pwm_omap_dmtimer_calc_value(clk_rate, period_ns);
- match_value = pwm_omap_dmtimer_calc_value(clk_rate,
- period_ns - duty_ns);
+ period_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, period_ns);
+ duty_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, duty_ns);
+
+ if (period_cycles < 2) {
+ dev_info(chip->dev,
+ "period %d ns too short for clock rate %lu Hz\n",
+ period_ns, clk_rate);
+ goto err_einval;
+ }
+
+ if (duty_cycles < 1) {
+ dev_dbg(chip->dev,
+ "duty cycle %d ns is too short for clock rate %lu Hz\n",
+ duty_ns, clk_rate);
+ dev_dbg(chip->dev, "using minimum of 1 clock cycle\n");
+ duty_cycles = 1;
+ } else if (duty_cycles >= period_cycles) {
+ dev_dbg(chip->dev,
+ "duty cycle %d ns is too long for period %d ns at clock rate %lu Hz\n",
+ duty_ns, period_ns, clk_rate);
+ dev_dbg(chip->dev, "using maximum of 1 clock cycle less than period\n");
+ duty_cycles = period_cycles - 1;
+ }
+
+ dev_dbg(chip->dev, "effective duty cycle: %lld ns, period: %lld ns\n",
+ DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * duty_cycles,
+ clk_rate),
+ DIV_ROUND_CLOSEST_ULL((u64)NSEC_PER_SEC * period_cycles,
+ clk_rate));
+
+ load_value = (DM_TIMER_MAX - period_cycles) + 1;
+ match_value = load_value + duty_cycles - 1;
/*
* We MUST stop the associated dual-mode timer before attempting to
@@ -166,6 +203,11 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
mutex_unlock(&omap->mutex);
return 0;
+
+err_einval:
+ mutex_unlock(&omap->mutex);
+
+ return -EINVAL;
}
static int pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip,