[PATCH v5 19/27] pwm: ti: am33xx: add enhanced pwm driver
Dario Binacchi
dariobin at libero.it
Sun Oct 25 13:40:02 CET 2020
Enhanced high resolution PWM module (EHRPWM) hardware can be used to
generate PWM output over 2 channels. This commit adds PWM driver support
for EHRPWM device present on AM33XX SOC.
The code is based on the drivers/pwm/pwm-tiehrpwm.c driver of the Linux
kernel version 5.9-rc7.
For DT binding details see:
- Documentation/devicetree/bindings/pwm/pwm-tiehrpwm.txt
Signed-off-by: Dario Binacchi <dariobin at libero.it>
---
(no changes since v4)
Changes in v4:
- Include device_compat.h header for dev_xxx macros.
Changes in v3:
- Adds PWM_TI_EHRPWM dependency on ARCH_OMAP2PLUS in Kconfig.
- Add error message in case of invalid address.
- Remove doc/device-tree-bindings/pwm/ti,ehrpwm.txt.
- Add to commit message the references to linux kernel dt binding
documentation.
drivers/pwm/Kconfig | 7 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-ti-ehrpwm.c | 468 ++++++++++++++++++++++++++++++++++++
3 files changed, 476 insertions(+)
create mode 100644 drivers/pwm/pwm-ti-ehrpwm.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index b3bd5c6bb7..ccf81abbe9 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -75,3 +75,10 @@ config PWM_SUNXI
help
This PWM is found on H3, A64 and other Allwinner SoCs. It supports a
programmable period and duty cycle. A 16-bit counter is used.
+
+config PWM_TI_EHRPWM
+ bool "Enable support for EHRPWM PWM"
+ depends on DM_PWM && ARCH_OMAP2PLUS
+ default y
+ help
+ PWM driver support for the EHRPWM controller found on TI SOCs.
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index f21ae7d76e..0b9d2698a3 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -19,3 +19,4 @@ obj-$(CONFIG_PWM_SANDBOX) += sandbox_pwm.o
obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
obj-$(CONFIG_PWM_TEGRA) += tegra_pwm.o
obj-$(CONFIG_PWM_SUNXI) += sunxi_pwm.o
+obj-$(CONFIG_PWM_TI_EHRPWM) += pwm-ti-ehrpwm.o
diff --git a/drivers/pwm/pwm-ti-ehrpwm.c b/drivers/pwm/pwm-ti-ehrpwm.c
new file mode 100644
index 0000000000..df995c8865
--- /dev/null
+++ b/drivers/pwm/pwm-ti-ehrpwm.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * EHRPWM PWM driver
+ *
+ * Copyright (C) 2020 Dario Binacchi <dariobin at libero.it>
+ *
+ * Based on Linux kernel drivers/pwm/pwm-tiehrpwm.c
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <div64.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <pwm.h>
+#include <asm/io.h>
+
+#define NSEC_PER_SEC 1000000000L
+
+/* Time base module registers */
+#define TI_EHRPWM_TBCTL 0x00
+#define TI_EHRPWM_TBPRD 0x0A
+
+#define TI_EHRPWM_TBCTL_PRDLD_MASK BIT(3)
+#define TI_EHRPWM_TBCTL_PRDLD_SHDW 0
+#define TI_EHRPWM_TBCTL_PRDLD_IMDT BIT(3)
+#define TI_EHRPWM_TBCTL_CLKDIV_MASK GENMASK(12, 7)
+#define TI_EHRPWM_TBCTL_CTRMODE_MASK GENMASK(1, 0)
+#define TI_EHRPWM_TBCTL_CTRMODE_UP 0
+#define TI_EHRPWM_TBCTL_CTRMODE_DOWN BIT(0)
+#define TI_EHRPWM_TBCTL_CTRMODE_UPDOWN BIT(1)
+#define TI_EHRPWM_TBCTL_CTRMODE_FREEZE GENMASK(1, 0)
+
+#define TI_EHRPWM_TBCTL_HSPCLKDIV_SHIFT 7
+#define TI_EHRPWM_TBCTL_CLKDIV_SHIFT 10
+
+#define TI_EHRPWM_CLKDIV_MAX 7
+#define TI_EHRPWM_HSPCLKDIV_MAX 7
+#define TI_EHRPWM_PERIOD_MAX 0xFFFF
+
+/* Counter compare module registers */
+#define TI_EHRPWM_CMPA 0x12
+#define TI_EHRPWM_CMPB 0x14
+
+/* Action qualifier module registers */
+#define TI_EHRPWM_AQCTLA 0x16
+#define TI_EHRPWM_AQCTLB 0x18
+#define TI_EHRPWM_AQSFRC 0x1A
+#define TI_EHRPWM_AQCSFRC 0x1C
+
+#define TI_EHRPWM_AQCTL_CBU_MASK GENMASK(9, 8)
+#define TI_EHRPWM_AQCTL_CBU_FRCLOW BIT(8)
+#define TI_EHRPWM_AQCTL_CBU_FRCHIGH BIT(9)
+#define TI_EHRPWM_AQCTL_CBU_FRCTOGGLE GENMASK(9, 8)
+#define TI_EHRPWM_AQCTL_CAU_MASK GENMASK(5, 4)
+#define TI_EHRPWM_AQCTL_CAU_FRCLOW BIT(4)
+#define TI_EHRPWM_AQCTL_CAU_FRCHIGH BIT(5)
+#define TI_EHRPWM_AQCTL_CAU_FRCTOGGLE GENMASK(5, 4)
+#define TI_EHRPWM_AQCTL_PRD_MASK GENMASK(3, 2)
+#define TI_EHRPWM_AQCTL_PRD_FRCLOW BIT(2)
+#define TI_EHRPWM_AQCTL_PRD_FRCHIGH BIT(3)
+#define TI_EHRPWM_AQCTL_PRD_FRCTOGGLE GENMASK(3, 2)
+#define TI_EHRPWM_AQCTL_ZRO_MASK GENMASK(1, 0)
+#define TI_EHRPWM_AQCTL_ZRO_FRCLOW BIT(0)
+#define TI_EHRPWM_AQCTL_ZRO_FRCHIGH BIT(1)
+#define TI_EHRPWM_AQCTL_ZRO_FRCTOGGLE GENMASK(1, 0)
+
+#define TI_EHRPWM_AQCTL_CHANA_POLNORMAL (TI_EHRPWM_AQCTL_CAU_FRCLOW | \
+ TI_EHRPWM_AQCTL_PRD_FRCHIGH | \
+ TI_EHRPWM_AQCTL_ZRO_FRCHIGH)
+#define TI_EHRPWM_AQCTL_CHANA_POLINVERSED (TI_EHRPWM_AQCTL_CAU_FRCHIGH | \
+ TI_EHRPWM_AQCTL_PRD_FRCLOW | \
+ TI_EHRPWM_AQCTL_ZRO_FRCLOW)
+#define TI_EHRPWM_AQCTL_CHANB_POLNORMAL (TI_EHRPWM_AQCTL_CBU_FRCLOW | \
+ TI_EHRPWM_AQCTL_PRD_FRCHIGH | \
+ TI_EHRPWM_AQCTL_ZRO_FRCHIGH)
+#define TI_EHRPWM_AQCTL_CHANB_POLINVERSED (TI_EHRPWM_AQCTL_CBU_FRCHIGH | \
+ TI_EHRPWM_AQCTL_PRD_FRCLOW | \
+ TI_EHRPWM_AQCTL_ZRO_FRCLOW)
+
+#define TI_EHRPWM_AQSFRC_RLDCSF_MASK GENMASK(7, 6)
+#define TI_EHRPWM_AQSFRC_RLDCSF_ZRO 0
+#define TI_EHRPWM_AQSFRC_RLDCSF_PRD BIT(6)
+#define TI_EHRPWM_AQSFRC_RLDCSF_ZROPRD BIT(7)
+#define TI_EHRPWM_AQSFRC_RLDCSF_IMDT GENMASK(7, 6)
+
+#define TI_EHRPWM_AQCSFRC_CSFB_MASK GENMASK(3, 2)
+#define TI_EHRPWM_AQCSFRC_CSFB_FRCDIS 0
+#define TI_EHRPWM_AQCSFRC_CSFB_FRCLOW BIT(2)
+#define TI_EHRPWM_AQCSFRC_CSFB_FRCHIGH BIT(3)
+#define TI_EHRPWM_AQCSFRC_CSFB_DISSWFRC GENMASK(3, 2)
+#define TI_EHRPWM_AQCSFRC_CSFA_MASK GENMASK(1, 0)
+#define TI_EHRPWM_AQCSFRC_CSFA_FRCDIS 0
+#define TI_EHRPWM_AQCSFRC_CSFA_FRCLOW BIT(0)
+#define TI_EHRPWM_AQCSFRC_CSFA_FRCHIGH BIT(1)
+#define TI_EHRPWM_AQCSFRC_CSFA_DISSWFRC GENMASK(1, 0)
+
+#define TI_EHRPWM_NUM_CHANNELS 2
+
+struct ti_ehrpwm_priv {
+ fdt_addr_t regs;
+ u32 clk_rate;
+ struct clk tbclk;
+ unsigned long period_cycles[TI_EHRPWM_NUM_CHANNELS];
+ bool polarity_reversed[TI_EHRPWM_NUM_CHANNELS];
+};
+
+static void ti_ehrpwm_modify(u16 val, u16 mask, fdt_addr_t reg)
+{
+ unsigned short v;
+
+ v = readw(reg);
+ v &= ~mask;
+ v |= val & mask;
+ writew(v, reg);
+}
+
+static int ti_ehrpwm_set_invert(struct udevice *dev, uint channel,
+ bool polarity)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+
+ if (channel >= TI_EHRPWM_NUM_CHANNELS)
+ return -ENOSPC;
+
+ /* Configuration of polarity in hardware delayed, do at enable */
+ priv->polarity_reversed[channel] = polarity;
+ return 0;
+}
+
+/**
+ * set_prescale_div - Set up the prescaler divider function
+ * @rqst_prescaler: prescaler value min
+ * @prescale_div: prescaler value set
+ * @tb_clk_div: Time Base Control prescaler bits
+ */
+static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div,
+ u16 *tb_clk_div)
+{
+ unsigned int clkdiv, hspclkdiv;
+
+ for (clkdiv = 0; clkdiv <= TI_EHRPWM_CLKDIV_MAX; clkdiv++) {
+ for (hspclkdiv = 0; hspclkdiv <= TI_EHRPWM_HSPCLKDIV_MAX;
+ hspclkdiv++) {
+ /*
+ * calculations for prescaler value :
+ * prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
+ * HSPCLKDIVIDER = 2 ** hspclkdiv
+ * CLKDIVIDER = (1), if clkdiv == 0 *OR*
+ * (2 * clkdiv), if clkdiv != 0
+ *
+ * Configure prescale_div value such that period
+ * register value is less than 65535.
+ */
+
+ *prescale_div = (1 << clkdiv) *
+ (hspclkdiv ? (hspclkdiv * 2) : 1);
+ if (*prescale_div > rqst_prescaler) {
+ *tb_clk_div =
+ (clkdiv << TI_EHRPWM_TBCTL_CLKDIV_SHIFT) |
+ (hspclkdiv <<
+ TI_EHRPWM_TBCTL_HSPCLKDIV_SHIFT);
+ return 0;
+ }
+ }
+ }
+
+ return 1;
+}
+
+static void ti_ehrpwm_configure_polarity(struct udevice *dev, uint channel)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+ u16 aqctl_val, aqctl_mask;
+ unsigned int aqctl_reg;
+
+ /*
+ * Configure PWM output to HIGH/LOW level on counter
+ * reaches compare register value and LOW/HIGH level
+ * on counter value reaches period register value and
+ * zero value on counter
+ */
+ if (channel == 1) {
+ aqctl_reg = TI_EHRPWM_AQCTLB;
+ aqctl_mask = TI_EHRPWM_AQCTL_CBU_MASK;
+
+ if (priv->polarity_reversed[channel])
+ aqctl_val = TI_EHRPWM_AQCTL_CHANB_POLINVERSED;
+ else
+ aqctl_val = TI_EHRPWM_AQCTL_CHANB_POLNORMAL;
+ } else {
+ aqctl_reg = TI_EHRPWM_AQCTLA;
+ aqctl_mask = TI_EHRPWM_AQCTL_CAU_MASK;
+
+ if (priv->polarity_reversed[channel])
+ aqctl_val = TI_EHRPWM_AQCTL_CHANA_POLINVERSED;
+ else
+ aqctl_val = TI_EHRPWM_AQCTL_CHANA_POLNORMAL;
+ }
+
+ aqctl_mask |= TI_EHRPWM_AQCTL_PRD_MASK | TI_EHRPWM_AQCTL_ZRO_MASK;
+ ti_ehrpwm_modify(aqctl_val, aqctl_mask, priv->regs + aqctl_reg);
+}
+
+/*
+ * period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
+ * duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
+ */
+static int ti_ehrpwm_set_config(struct udevice *dev, uint channel,
+ uint period_ns, uint duty_ns)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+ u32 period_cycles, duty_cycles;
+ u16 ps_divval, tb_divval;
+ unsigned int i, cmp_reg;
+ unsigned long long c;
+
+ if (channel >= TI_EHRPWM_NUM_CHANNELS)
+ return -ENOSPC;
+
+ if (period_ns > NSEC_PER_SEC)
+ return -ERANGE;
+
+ c = priv->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 = priv->clk_rate;
+ c = c * duty_ns;
+ do_div(c, NSEC_PER_SEC);
+ duty_cycles = (unsigned long)c;
+ }
+
+ dev_dbg(dev, "channel=%d, period_ns=%d, duty_ns=%d\n",
+ channel, period_ns, duty_ns);
+
+ /*
+ * Period values should be same for multiple PWM channels as IP uses
+ * same period register for multiple channels.
+ */
+ for (i = 0; i < TI_EHRPWM_NUM_CHANNELS; i++) {
+ if (priv->period_cycles[i] &&
+ priv->period_cycles[i] != period_cycles) {
+ /*
+ * Allow channel to reconfigure period if no other
+ * channels being configured.
+ */
+ if (i == channel)
+ continue;
+
+ dev_err(dev, "period value conflicts with channel %u\n",
+ i);
+ return -EINVAL;
+ }
+ }
+
+ priv->period_cycles[channel] = period_cycles;
+
+ /* Configure clock prescaler to support Low frequency PWM wave */
+ if (set_prescale_div(period_cycles / TI_EHRPWM_PERIOD_MAX, &ps_divval,
+ &tb_divval)) {
+ dev_err(dev, "unsupported values\n");
+ return -EINVAL;
+ }
+
+ /* Update clock prescaler values */
+ ti_ehrpwm_modify(tb_divval, TI_EHRPWM_TBCTL_CLKDIV_MASK,
+ priv->regs + TI_EHRPWM_TBCTL);
+
+ /* Update period & duty cycle with presacler division */
+ period_cycles = period_cycles / ps_divval;
+ duty_cycles = duty_cycles / ps_divval;
+
+ /* Configure shadow loading on Period register */
+ ti_ehrpwm_modify(TI_EHRPWM_TBCTL_PRDLD_SHDW, TI_EHRPWM_TBCTL_PRDLD_MASK,
+ priv->regs + TI_EHRPWM_TBCTL);
+
+ writew(period_cycles, priv->regs + TI_EHRPWM_TBPRD);
+
+ /* Configure ehrpwm counter for up-count mode */
+ ti_ehrpwm_modify(TI_EHRPWM_TBCTL_CTRMODE_UP,
+ TI_EHRPWM_TBCTL_CTRMODE_MASK,
+ priv->regs + TI_EHRPWM_TBCTL);
+
+ if (channel == 1)
+ /* Channel 1 configured with compare B register */
+ cmp_reg = TI_EHRPWM_CMPB;
+ else
+ /* Channel 0 configured with compare A register */
+ cmp_reg = TI_EHRPWM_CMPA;
+
+ writew(duty_cycles, priv->regs + cmp_reg);
+ return 0;
+}
+
+static int ti_ehrpwm_disable(struct udevice *dev, uint channel)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+ u16 aqcsfrc_val, aqcsfrc_mask;
+ int err;
+
+ if (channel >= TI_EHRPWM_NUM_CHANNELS)
+ return -ENOSPC;
+
+ /* Action Qualifier puts PWM output low forcefully */
+ if (channel) {
+ aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFB_FRCLOW;
+ aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFB_MASK;
+ } else {
+ aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFA_FRCLOW;
+ aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFA_MASK;
+ }
+
+ /* Update shadow register first before modifying active register */
+ ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_ZRO,
+ TI_EHRPWM_AQSFRC_RLDCSF_MASK,
+ priv->regs + TI_EHRPWM_AQSFRC);
+
+ ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
+ priv->regs + TI_EHRPWM_AQCSFRC);
+
+ /*
+ * Changes to immediate action on Action Qualifier. This puts
+ * Action Qualifier control on PWM output from next TBCLK
+ */
+ ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_IMDT,
+ TI_EHRPWM_AQSFRC_RLDCSF_MASK,
+ priv->regs + TI_EHRPWM_AQSFRC);
+
+ ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
+ priv->regs + TI_EHRPWM_AQCSFRC);
+
+ /* Disabling TBCLK on PWM disable */
+ err = clk_disable(&priv->tbclk);
+ if (err) {
+ dev_err(dev, "failed to disable tbclk\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static int ti_ehrpwm_enable(struct udevice *dev, uint channel)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+ u16 aqcsfrc_val, aqcsfrc_mask;
+ int err;
+
+ if (channel >= TI_EHRPWM_NUM_CHANNELS)
+ return -ENOSPC;
+
+ /* Disabling Action Qualifier on PWM output */
+ if (channel) {
+ aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFB_FRCDIS;
+ aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFB_MASK;
+ } else {
+ aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFA_FRCDIS;
+ aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFA_MASK;
+ }
+
+ /* Changes to shadow mode */
+ ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_ZRO,
+ TI_EHRPWM_AQSFRC_RLDCSF_MASK,
+ priv->regs + TI_EHRPWM_AQSFRC);
+
+ ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
+ priv->regs + TI_EHRPWM_AQCSFRC);
+
+ /* Channels polarity can be configured from action qualifier module */
+ ti_ehrpwm_configure_polarity(dev, channel);
+
+ err = clk_enable(&priv->tbclk);
+ if (err) {
+ dev_err(dev, "failed to enable tbclk\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static int ti_ehrpwm_set_enable(struct udevice *dev, uint channel, bool enable)
+{
+ if (enable)
+ return ti_ehrpwm_enable(dev, channel);
+
+ return ti_ehrpwm_disable(dev, channel);
+}
+
+static int ti_ehrpwm_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+
+ priv->regs = dev_read_addr(dev);
+ if (priv->regs == FDT_ADDR_T_NONE) {
+ dev_err(dev, "invalid address\n");
+ return -EINVAL;
+ }
+
+ dev_dbg(dev, "regs=0x%08lx\n", priv->regs);
+ return 0;
+}
+
+static int ti_ehrpwm_remove(struct udevice *dev)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+
+ clk_release_all(&priv->tbclk, 1);
+ return 0;
+}
+
+static int ti_ehrpwm_probe(struct udevice *dev)
+{
+ struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ int err;
+
+ err = clk_get_by_name(dev, "fck", &clk);
+ if (err) {
+ dev_err(dev, "failed to get clock\n");
+ return err;
+ }
+
+ priv->clk_rate = clk_get_rate(&clk);
+ if (IS_ERR_VALUE(priv->clk_rate) || !priv->clk_rate) {
+ dev_err(dev, "failed to get clock rate\n");
+ if (IS_ERR_VALUE(priv->clk_rate))
+ return priv->clk_rate;
+
+ return -EINVAL;
+ }
+
+ /* Acquire tbclk for Time Base EHRPWM submodule */
+ err = clk_get_by_name(dev, "tbclk", &priv->tbclk);
+ if (err) {
+ dev_err(dev, "failed to get tbclk clock\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static const struct pwm_ops ti_ehrpwm_ops = {
+ .set_config = ti_ehrpwm_set_config,
+ .set_enable = ti_ehrpwm_set_enable,
+ .set_invert = ti_ehrpwm_set_invert,
+};
+
+static const struct udevice_id ti_ehrpwm_ids[] = {
+ {.compatible = "ti,am3352-ehrpwm"},
+ {.compatible = "ti,am33xx-ehrpwm"},
+ {}
+};
+
+U_BOOT_DRIVER(ti_ehrpwm) = {
+ .name = "ti_ehrpwm",
+ .id = UCLASS_PWM,
+ .of_match = ti_ehrpwm_ids,
+ .ops = &ti_ehrpwm_ops,
+ .ofdata_to_platdata = ti_ehrpwm_ofdata_to_platdata,
+ .probe = ti_ehrpwm_probe,
+ .remove = ti_ehrpwm_remove,
+ .priv_auto_alloc_size = sizeof(struct ti_ehrpwm_priv),
+};
--
2.17.1
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