| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * drivers/pwm/pwm-pxa.c |
| 4 | * |
| 5 | * simple driver for PWM (Pulse Width Modulator) controller |
| 6 | * |
| 7 | * 2008-02-13 initial version |
| 8 | * eric miao <eric.miao@marvell.com> |
| 9 | * |
| 10 | * Links to reference manuals for some of the supported PWM chips can be found |
| 11 | * in Documentation/arch/arm/marvell.rst. |
| 12 | * |
| 13 | * Limitations: |
| 14 | * - When PWM is stopped, the current PWM period stops abruptly at the next |
| 15 | * input clock (PWMCR_SD is set) and the output is driven to inactive. |
| 16 | */ |
| 17 | |
| 18 | #include <linux/mod_devicetable.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/slab.h> |
| 23 | #include <linux/err.h> |
| 24 | #include <linux/clk.h> |
| 25 | #include <linux/io.h> |
| 26 | #include <linux/pwm.h> |
| 27 | #include <linux/of.h> |
| 28 | |
| 29 | #include <asm/div64.h> |
| 30 | |
| 31 | #define HAS_SECONDARY_PWM 0x10 |
| 32 | |
| 33 | static const struct platform_device_id pwm_id_table[] = { |
| 34 | /* PWM has_secondary_pwm? */ |
| 35 | { "pxa25x-pwm", 0 }, |
| 36 | { "pxa27x-pwm", HAS_SECONDARY_PWM }, |
| 37 | { "pxa168-pwm", 0 }, |
| 38 | { "pxa910-pwm", 0 }, |
| 39 | { }, |
| 40 | }; |
| 41 | MODULE_DEVICE_TABLE(platform, pwm_id_table); |
| 42 | |
| 43 | /* PWM registers and bits definitions */ |
| 44 | #define PWMCR (0x00) |
| 45 | #define PWMDCR (0x04) |
| 46 | #define PWMPCR (0x08) |
| 47 | |
| 48 | #define PWMCR_SD (1 << 6) |
| 49 | #define PWMDCR_FD (1 << 10) |
| 50 | |
| 51 | struct pxa_pwm_chip { |
| 52 | struct device *dev; |
| 53 | |
| 54 | struct clk *clk; |
| 55 | void __iomem *mmio_base; |
| 56 | }; |
| 57 | |
| 58 | static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip) |
| 59 | { |
| 60 | return pwmchip_get_drvdata(chip); |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE |
| 65 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE |
| 66 | */ |
| 67 | static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 68 | u64 duty_ns, u64 period_ns) |
| 69 | { |
| 70 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
| 71 | unsigned long long c; |
| 72 | unsigned long period_cycles, prescale, pv, dc; |
| 73 | unsigned long offset; |
| 74 | |
| 75 | offset = pwm->hwpwm ? 0x10 : 0; |
| 76 | |
| 77 | c = clk_get_rate(pc->clk); |
| 78 | c = c * period_ns; |
| 79 | do_div(c, 1000000000); |
| 80 | period_cycles = c; |
| 81 | |
| 82 | if (period_cycles < 1) |
| 83 | period_cycles = 1; |
| 84 | prescale = (period_cycles - 1) / 1024; |
| 85 | pv = period_cycles / (prescale + 1) - 1; |
| 86 | |
| 87 | if (prescale > 63) |
| 88 | return -EINVAL; |
| 89 | |
| 90 | if (duty_ns == period_ns) |
| 91 | dc = PWMDCR_FD; |
| 92 | else |
| 93 | dc = mul_u64_u64_div_u64(pv + 1, duty_ns, period_ns); |
| 94 | |
| 95 | writel(prescale | PWMCR_SD, pc->mmio_base + offset + PWMCR); |
| 96 | writel(dc, pc->mmio_base + offset + PWMDCR); |
| 97 | writel(pv, pc->mmio_base + offset + PWMPCR); |
| 98 | |
| 99 | return 0; |
| 100 | } |
| 101 | |
| 102 | static int pxa_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, |
| 103 | const struct pwm_state *state) |
| 104 | { |
| 105 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
| 106 | u64 duty_cycle; |
| 107 | int err; |
| 108 | |
| 109 | if (state->polarity != PWM_POLARITY_NORMAL) |
| 110 | return -EINVAL; |
| 111 | |
| 112 | err = clk_prepare_enable(pc->clk); |
| 113 | if (err) |
| 114 | return err; |
| 115 | |
| 116 | duty_cycle = state->enabled ? state->duty_cycle : 0; |
| 117 | |
| 118 | err = pxa_pwm_config(chip, pwm, duty_cycle, state->period); |
| 119 | if (err) { |
| 120 | clk_disable_unprepare(pc->clk); |
| 121 | return err; |
| 122 | } |
| 123 | |
| 124 | if (state->enabled && !pwm->state.enabled) |
| 125 | return 0; |
| 126 | |
| 127 | clk_disable_unprepare(pc->clk); |
| 128 | |
| 129 | if (!state->enabled && pwm->state.enabled) |
| 130 | clk_disable_unprepare(pc->clk); |
| 131 | |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | static const struct pwm_ops pxa_pwm_ops = { |
| 136 | .apply = pxa_pwm_apply, |
| 137 | }; |
| 138 | |
| 139 | #ifdef CONFIG_OF |
| 140 | /* |
| 141 | * Device tree users must create one device instance for each PWM channel. |
| 142 | * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver |
| 143 | * code that this is a single channel pxa25x-pwm. Currently all devices are |
| 144 | * supported identically. |
| 145 | */ |
| 146 | static const struct of_device_id pwm_of_match[] = { |
| 147 | { .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]}, |
| 148 | { .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]}, |
| 149 | { .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]}, |
| 150 | { .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]}, |
| 151 | { } |
| 152 | }; |
| 153 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
| 154 | #else |
| 155 | #define pwm_of_match NULL |
| 156 | #endif |
| 157 | |
| 158 | static int pwm_probe(struct platform_device *pdev) |
| 159 | { |
| 160 | const struct platform_device_id *id = platform_get_device_id(pdev); |
| 161 | struct pwm_chip *chip; |
| 162 | struct pxa_pwm_chip *pc; |
| 163 | int ret = 0; |
| 164 | |
| 165 | if (IS_ENABLED(CONFIG_OF) && id == NULL) |
| 166 | id = of_device_get_match_data(&pdev->dev); |
| 167 | |
| 168 | if (id == NULL) |
| 169 | return -EINVAL; |
| 170 | |
| 171 | chip = devm_pwmchip_alloc(&pdev->dev, |
| 172 | (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1, |
| 173 | sizeof(*pc)); |
| 174 | if (IS_ERR(chip)) |
| 175 | return PTR_ERR(chip); |
| 176 | pc = to_pxa_pwm_chip(chip); |
| 177 | |
| 178 | pc->clk = devm_clk_get(&pdev->dev, NULL); |
| 179 | if (IS_ERR(pc->clk)) |
| 180 | return PTR_ERR(pc->clk); |
| 181 | |
| 182 | chip->ops = &pxa_pwm_ops; |
| 183 | |
| 184 | if (IS_ENABLED(CONFIG_OF)) |
| 185 | chip->of_xlate = of_pwm_single_xlate; |
| 186 | |
| 187 | pc->mmio_base = devm_platform_ioremap_resource(pdev, 0); |
| 188 | if (IS_ERR(pc->mmio_base)) |
| 189 | return PTR_ERR(pc->mmio_base); |
| 190 | |
| 191 | ret = devm_pwmchip_add(&pdev->dev, chip); |
| 192 | if (ret < 0) { |
| 193 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); |
| 194 | return ret; |
| 195 | } |
| 196 | |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | static struct platform_driver pwm_driver = { |
| 201 | .driver = { |
| 202 | .name = "pxa25x-pwm", |
| 203 | .of_match_table = pwm_of_match, |
| 204 | }, |
| 205 | .probe = pwm_probe, |
| 206 | .id_table = pwm_id_table, |
| 207 | }; |
| 208 | |
| 209 | module_platform_driver(pwm_driver); |
| 210 | |
| 211 | MODULE_LICENSE("GPL v2"); |