On 8/30/21 6:03 PM, Sean Anderson wrote:
On 8/30/21 5:38 AM, Michal Simek wrote:
TTC has three modes of operations. Timer, PWM and input counters.
There is already driver for timer under CADENCE_TTC_TIMER which is used for ZynqMP R5 configuration. This driver is targeting PWM which is for example configuration which can be used for fan control. The driver has been tested on Xilinx Kria SOM platform where fan is connected to one PL pin. When TTC output is connected via EMIO to PL pin TTC pwm can be configured and tested for example like this: pwm config 0 0 10000 1200 pwm enable 0 0 pwm config 0 0 10000 1400 pwm config 0 0 10000 1600
Signed-off-by: Michal Simek michal.simek@xilinx.com
Changes in v2:
- Detect pwm-cells property for PWM driver
- Fix all macro names
- Use BIT and GENMASK macros
- Introduce TTC_REG macro for reg offsets
- Use FIELD_PREP
- Move cadence_ttc_pwm_of_to_plat() below probe
- Introduce struct cadence_ttc_pwm_plat
- Read timer-width from DT
- Use NSEC_PER_SEC macro
- Use clock_ctrl variable instead of x - all reported by Sean
MAINTAINERS | 1 + drivers/pwm/Kconfig | 7 + drivers/pwm/Makefile | 1 + drivers/pwm/pwm-cadence-ttc.c | 247 ++++++++++++++++++++++++++++++++++ 4 files changed, 256 insertions(+) create mode 100644 drivers/pwm/pwm-cadence-ttc.c
diff --git a/MAINTAINERS b/MAINTAINERS index 4cf0c33c5d58..889813382249 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -600,6 +600,7 @@ F: drivers/mmc/zynq_sdhci.c F: drivers/mtd/nand/raw/zynq_nand.c F: drivers/net/phy/xilinx_phy.c F: drivers/net/zynq_gem.c +F: drivers/pwm/pwm-cadence-ttc.c F: drivers/serial/serial_zynq.c F: drivers/reset/reset-zynqmp.c F: drivers/rtc/zynqmp_rtc.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index cf7f4c6840ce..176e703c8fbb 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -9,6 +9,13 @@ config DM_PWM frequency/period can be controlled along with the proportion of that time that the signal is high.
+config PWM_CADENCE_TTC + bool "Enable support for the Cadence TTC PWM" + depends on DM_PWM && !CADENCE_TTC_TIMER + help + Cadence TTC can be configured as timer which is done via + CONFIG_CADENCE_TTC_TIMER or as PWM. This is covering only PWM now.
config PWM_CROS_EC bool "Enable support for the Chrome OS EC PWM" depends on DM_PWM diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 10d244bfb79d..abf5af41d2cc 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -10,6 +10,7 @@
obj-$(CONFIG_DM_PWM) += pwm-uclass.o
+obj-$(CONFIG_PWM_CADENCE_TTC) += pwm-cadence-ttc.o obj-$(CONFIG_PWM_CROS_EC) += cros_ec_pwm.o obj-$(CONFIG_PWM_EXYNOS) += exynos_pwm.o obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o diff --git a/drivers/pwm/pwm-cadence-ttc.c b/drivers/pwm/pwm-cadence-ttc.c new file mode 100644 index 000000000000..99aaaa6a8ab6 --- /dev/null +++ b/drivers/pwm/pwm-cadence-ttc.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- (C) Copyright 2021 Xilinx, Inc. Michal Simek
- */
+#include <clk.h> +#include <common.h> +#include <div64.h> +#include <dm.h> +#include <log.h> +#include <pwm.h> +#include <asm/io.h> +#include <log.h> +#include <div64.h> +#include <linux/bitfield.h> +#include <linux/math64.h> +#include <linux/log2.h> +#include <dm/device_compat.h>
+#define CLOCK_CONTROL 0 +#define COUNTER_CONTROL 0xc +#define INTERVAL_COUNTER 0x24 +#define MATCH_1_COUNTER 0x30
+#define CLK_FALLING_EDGE BIT(6) +#define CLK_SRC_EXTERNAL BIT(5) +#define CLK_PRESCALE_MASK GENMASK(4, 1) +#define CLK_PRESCALE_ENABLE BIT(0)
+#define COUNTER_WAVE_POL BIT(6) +#define COUNTER_WAVE_DISABLE BIT(5) +#define COUNTER_RESET BIT(4) +#define COUNTER_MATCH_ENABLE BIT(3) +#define COUNTER_DECREMENT_ENABLE BIT(2) +#define COUNTER_INTERVAL_ENABLE BIT(1) +#define COUNTER_COUNTING_DISABLE BIT(0)
+#define NSEC_PER_SEC 1000000000L
+#define TTC_REG(reg, channel) ((reg) + (channel) * sizeof(u32)) +#define TTC_CLOCK_CONTROL(reg, channel) \ + TTC_REG((reg) + CLOCK_CONTROL, (channel)) +#define TTC_COUNTER_CONTROL(reg, channel) \ + TTC_REG((reg) + COUNTER_CONTROL, (channel)) +#define TTC_INTERVAL_COUNTER(reg, channel) \ + TTC_REG((reg) + INTERVAL_COUNTER, (channel)) +#define TTC_MATCH_1_COUNTER(reg, channel) \ + TTC_REG((reg) + MATCH_1_COUNTER, (channel))
+struct cadence_ttc_pwm_plat { + u8 *regs; + u32 timer_mask; +};
+struct cadence_ttc_pwm_priv { + u8 *regs; + u32 timer_mask; + unsigned long frequency; + bool invert[2]; +};
+static int cadence_ttc_pwm_set_invert(struct udevice *dev, uint channel, + bool polarity) +{ + struct cadence_ttc_pwm_priv *priv = dev_get_priv(dev);
+ if (channel > 2) { + dev_err(dev, "Unsupported channel number %d(max 2)\n", channel); + return -EINVAL; + }
+ priv->invert[channel] = polarity;
+ dev_dbg(dev, "polarity=%u. Please config PWM again\n", polarity);
+ return 0; +}
+static int cadence_ttc_pwm_set_config(struct udevice *dev, uint channel, + uint period_ns, uint duty_ns) +{ + struct cadence_ttc_pwm_priv *priv = dev_get_priv(dev); + u32 counter_ctrl, clock_ctrl; + int period_clocks, duty_clocks, prescaler;
+ dev_dbg(dev, "channel %d, duty %d/ period %d ns\n", channel, + duty_ns, period_ns);
+ if (channel > 2) { + dev_err(dev, "Unsupported channel number %d(max 2)\n", channel); + return -EINVAL; + }
+ /* Make sure counter is stopped */ + counter_ctrl = readl(TTC_COUNTER_CONTROL(priv->regs, channel)); + setbits_le32(TTC_COUNTER_CONTROL(priv->regs, channel), + COUNTER_COUNTING_DISABLE);
Why disable it?
it should be better to disable it then changing values with output enabled.
+ /* Calculate period, prescaler and set clock control register */ + period_clocks = div64_u64(((int64_t)period_ns * priv->frequency), + NSEC_PER_SEC);
+ prescaler = ilog2(period_clocks) + 1 - 16;
This 16 should be based off of priv->timer_mask.
done in v2
+ if (prescaler < 0) + prescaler = 0;
+ clock_ctrl = readl(TTC_CLOCK_CONTROL(priv->regs, channel));
+ if (!prescaler) { + clock_ctrl &= ~(CLK_PRESCALE_ENABLE | CLK_PRESCALE_MASK); + } else { + clock_ctrl &= ~CLK_PRESCALE_MASK; + clock_ctrl |= CLK_PRESCALE_ENABLE; + clock_ctrl |= FIELD_PREP(CLK_PRESCALE_MASK, prescaler - 1); + };
+ /* External source is not handled by this driver now */ + clock_ctrl &= ~CLK_SRC_EXTERNAL;
+ writel(clock_ctrl, TTC_CLOCK_CONTROL(priv->regs, channel));
+ /* Calculate interval and set counter control value */ + duty_clocks = div64_u64(((int64_t)duty_ns * priv->frequency), + NSEC_PER_SEC);
+ writel((period_clocks >> prescaler) & priv->timer_mask, + TTC_INTERVAL_COUNTER(priv->regs, channel)); + writel((duty_clocks >> prescaler) & priv->timer_mask, + TTC_MATCH_1_COUNTER(priv->regs, channel));
+ /* Restore/reset counter */ + counter_ctrl &= ~COUNTER_DECREMENT_ENABLE; + counter_ctrl |= COUNTER_INTERVAL_ENABLE | + COUNTER_RESET | + COUNTER_MATCH_ENABLE;
+ if (priv->invert[channel]) + counter_ctrl |= COUNTER_WAVE_POL; + else + counter_ctrl &= ~COUNTER_WAVE_POL;
+ writel(counter_ctrl, TTC_COUNTER_CONTROL(priv->regs, channel));
+ dev_dbg(dev, "%d/%d clocks, prescaler 2^%d\n", duty_clocks, + period_clocks, prescaler);
+ return 0; +};
+static int cadence_ttc_pwm_set_enable(struct udevice *dev, uint channel, + bool enable) +{ + struct cadence_ttc_pwm_priv *priv = dev_get_priv(dev);
+ if (channel > 2) { + dev_err(dev, "Unsupported channel number %d(max 2)\n", channel); + return -EINVAL; + }
+ dev_dbg(dev, "Enable: %d, channel %d\n", enable, channel);
+ if (enable) { + clrbits_le32(TTC_COUNTER_CONTROL(priv->regs, channel), + COUNTER_COUNTING_DISABLE | + COUNTER_WAVE_DISABLE); + setbits_le32(TTC_COUNTER_CONTROL(priv->regs, channel), + COUNTER_RESET); + } else { + setbits_le32(TTC_COUNTER_CONTROL(priv->regs, channel), + COUNTER_COUNTING_DISABLE | + COUNTER_WAVE_DISABLE); + }
+ return 0; +};
+static int cadence_ttc_pwm_probe(struct udevice *dev) +{ + struct cadence_ttc_pwm_priv *priv = dev_get_priv(dev); + struct cadence_ttc_pwm_plat *plat = dev_get_plat(dev); + struct clk clk; + int ret;
+ priv->regs = plat->regs; + priv->timer_mask = plat->timer_mask;
+ ret = clk_get_by_index(dev, 0, &clk); + if (ret < 0) { + dev_err(dev, "failed to get clock\n"); + return ret; + }
+ priv->frequency = clk_get_rate(&clk); + if (IS_ERR_VALUE(priv->frequency)) { + dev_err(dev, "failed to get rate\n"); + return priv->frequency; + } + dev_dbg(dev, "Clk frequency: %ld\n", priv->frequency);
+ ret = clk_enable(&clk); + if (ret) { + dev_err(dev, "failed to enable clock\n"); + return ret; + }
+ return 0; +}
+static int cadence_ttc_pwm_of_to_plat(struct udevice *dev) +{ + struct cadence_ttc_pwm_plat *plat = dev_get_plat(dev); + const char *cells; + u32 timer_width;
+ cells = dev_read_prop(dev, "#pwm-cells", NULL); + if (!cells) + return -EINVAL;
Sorry, I was not precise enough with my feedback last time. This check needs to happen in bind() (and return -ENODEV) so that lists_bind_fdt tries another driver.
I took a look at it and core doesn't support it without patching. When one driver returns -ENODEV core won't try to find another driver. But I have sent v3 series with small changes in the core to handle this case better. Also update cadence ttc timer driver to check pwm-cells and ignore it in that case. Even that's situation which is not a problem on arm64 which is not enabling CONFIG_TIMER.
Thanks, Michal