diff options
Diffstat (limited to 'drivers/clk/clk-vt8500.c')
-rw-r--r-- | drivers/clk/clk-vt8500.c | 753 |
1 files changed, 753 insertions, 0 deletions
diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c new file mode 100644 index 000000000..4161a6f25 --- /dev/null +++ b/drivers/clk/clk-vt8500.c @@ -0,0 +1,753 @@ +/* + * Clock implementation for VIA/Wondermedia SoC's + * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/slab.h> +#include <linux/bitops.h> +#include <linux/clkdev.h> +#include <linux/clk-provider.h> + +#define LEGACY_PMC_BASE 0xD8130000 + +/* All clocks share the same lock as none can be changed concurrently */ +static DEFINE_SPINLOCK(_lock); + +struct clk_device { + struct clk_hw hw; + void __iomem *div_reg; + unsigned int div_mask; + void __iomem *en_reg; + int en_bit; + spinlock_t *lock; +}; + +/* + * Add new PLL_TYPE_x definitions here as required. Use the first known model + * to support the new type as the name. + * Add case statements to vtwm_pll_recalc_rate(), vtwm_pll_round_round() and + * vtwm_pll_set_rate() to handle the new PLL_TYPE_x + */ + +#define PLL_TYPE_VT8500 0 +#define PLL_TYPE_WM8650 1 +#define PLL_TYPE_WM8750 2 +#define PLL_TYPE_WM8850 3 + +struct clk_pll { + struct clk_hw hw; + void __iomem *reg; + spinlock_t *lock; + int type; +}; + +static void __iomem *pmc_base; + +static __init void vtwm_set_pmc_base(void) +{ + struct device_node *np = + of_find_compatible_node(NULL, NULL, "via,vt8500-pmc"); + + if (np) + pmc_base = of_iomap(np, 0); + else + pmc_base = ioremap(LEGACY_PMC_BASE, 0x1000); + of_node_put(np); + + if (!pmc_base) + pr_err("%s:of_iomap(pmc) failed\n", __func__); +} + +#define to_clk_device(_hw) container_of(_hw, struct clk_device, hw) + +#define VT8500_PMC_BUSY_MASK 0x18 + +static void vt8500_pmc_wait_busy(void) +{ + while (readl(pmc_base) & VT8500_PMC_BUSY_MASK) + cpu_relax(); +} + +static int vt8500_dclk_enable(struct clk_hw *hw) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 en_val; + unsigned long flags = 0; + + spin_lock_irqsave(cdev->lock, flags); + + en_val = readl(cdev->en_reg); + en_val |= BIT(cdev->en_bit); + writel(en_val, cdev->en_reg); + + spin_unlock_irqrestore(cdev->lock, flags); + return 0; +} + +static void vt8500_dclk_disable(struct clk_hw *hw) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 en_val; + unsigned long flags = 0; + + spin_lock_irqsave(cdev->lock, flags); + + en_val = readl(cdev->en_reg); + en_val &= ~BIT(cdev->en_bit); + writel(en_val, cdev->en_reg); + + spin_unlock_irqrestore(cdev->lock, flags); +} + +static int vt8500_dclk_is_enabled(struct clk_hw *hw) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 en_val = (readl(cdev->en_reg) & BIT(cdev->en_bit)); + + return en_val ? 1 : 0; +} + +static unsigned long vt8500_dclk_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 div = readl(cdev->div_reg) & cdev->div_mask; + + /* Special case for SDMMC devices */ + if ((cdev->div_mask == 0x3F) && (div & BIT(5))) + div = 64 * (div & 0x1f); + + /* div == 0 is actually the highest divisor */ + if (div == 0) + div = (cdev->div_mask + 1); + + return parent_rate / div; +} + +static long vt8500_dclk_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 divisor; + + if (rate == 0) + return 0; + + divisor = *prate / rate; + + /* If prate / rate would be decimal, incr the divisor */ + if (rate * divisor < *prate) + divisor++; + + /* + * If this is a request for SDMMC we have to adjust the divisor + * when >31 to use the fixed predivisor + */ + if ((cdev->div_mask == 0x3F) && (divisor > 31)) { + divisor = 64 * ((divisor / 64) + 1); + } + + return *prate / divisor; +} + +static int vt8500_dclk_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_device *cdev = to_clk_device(hw); + u32 divisor; + unsigned long flags = 0; + + if (rate == 0) + return 0; + + divisor = parent_rate / rate; + + if (divisor == cdev->div_mask + 1) + divisor = 0; + + /* SDMMC mask may need to be corrected before testing if its valid */ + if ((cdev->div_mask == 0x3F) && (divisor > 31)) { + /* + * Bit 5 is a fixed /64 predivisor. If the requested divisor + * is >31 then correct for the fixed divisor being required. + */ + divisor = 0x20 + (divisor / 64); + } + + if (divisor > cdev->div_mask) { + pr_err("%s: invalid divisor for clock\n", __func__); + return -EINVAL; + } + + spin_lock_irqsave(cdev->lock, flags); + + vt8500_pmc_wait_busy(); + writel(divisor, cdev->div_reg); + vt8500_pmc_wait_busy(); + + spin_unlock_irqrestore(cdev->lock, flags); + + return 0; +} + + +static const struct clk_ops vt8500_gated_clk_ops = { + .enable = vt8500_dclk_enable, + .disable = vt8500_dclk_disable, + .is_enabled = vt8500_dclk_is_enabled, +}; + +static const struct clk_ops vt8500_divisor_clk_ops = { + .round_rate = vt8500_dclk_round_rate, + .set_rate = vt8500_dclk_set_rate, + .recalc_rate = vt8500_dclk_recalc_rate, +}; + +static const struct clk_ops vt8500_gated_divisor_clk_ops = { + .enable = vt8500_dclk_enable, + .disable = vt8500_dclk_disable, + .is_enabled = vt8500_dclk_is_enabled, + .round_rate = vt8500_dclk_round_rate, + .set_rate = vt8500_dclk_set_rate, + .recalc_rate = vt8500_dclk_recalc_rate, +}; + +#define CLK_INIT_GATED BIT(0) +#define CLK_INIT_DIVISOR BIT(1) +#define CLK_INIT_GATED_DIVISOR (CLK_INIT_DIVISOR | CLK_INIT_GATED) + +static __init void vtwm_device_clk_init(struct device_node *node) +{ + u32 en_reg, div_reg; + struct clk_hw *hw; + struct clk_device *dev_clk; + const char *clk_name = node->name; + const char *parent_name; + struct clk_init_data init; + int rc; + int clk_init_flags = 0; + + if (!pmc_base) + vtwm_set_pmc_base(); + + dev_clk = kzalloc(sizeof(*dev_clk), GFP_KERNEL); + if (WARN_ON(!dev_clk)) + return; + + dev_clk->lock = &_lock; + + rc = of_property_read_u32(node, "enable-reg", &en_reg); + if (!rc) { + dev_clk->en_reg = pmc_base + en_reg; + rc = of_property_read_u32(node, "enable-bit", &dev_clk->en_bit); + if (rc) { + pr_err("%s: enable-bit property required for gated clock\n", + __func__); + return; + } + clk_init_flags |= CLK_INIT_GATED; + } + + rc = of_property_read_u32(node, "divisor-reg", &div_reg); + if (!rc) { + dev_clk->div_reg = pmc_base + div_reg; + /* + * use 0x1f as the default mask since it covers + * almost all the clocks and reduces dts properties + */ + dev_clk->div_mask = 0x1f; + + of_property_read_u32(node, "divisor-mask", &dev_clk->div_mask); + clk_init_flags |= CLK_INIT_DIVISOR; + } + + of_property_read_string(node, "clock-output-names", &clk_name); + + switch (clk_init_flags) { + case CLK_INIT_GATED: + init.ops = &vt8500_gated_clk_ops; + break; + case CLK_INIT_DIVISOR: + init.ops = &vt8500_divisor_clk_ops; + break; + case CLK_INIT_GATED_DIVISOR: + init.ops = &vt8500_gated_divisor_clk_ops; + break; + default: + pr_err("%s: Invalid clock description in device tree\n", + __func__); + kfree(dev_clk); + return; + } + + init.name = clk_name; + init.flags = 0; + parent_name = of_clk_get_parent_name(node, 0); + init.parent_names = &parent_name; + init.num_parents = 1; + + dev_clk->hw.init = &init; + + hw = &dev_clk->hw; + rc = clk_hw_register(NULL, hw); + if (WARN_ON(rc)) { + kfree(dev_clk); + return; + } + rc = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw); + clk_hw_register_clkdev(hw, clk_name, NULL); +} +CLK_OF_DECLARE(vt8500_device, "via,vt8500-device-clock", vtwm_device_clk_init); + +/* PLL clock related functions */ + +#define to_clk_pll(_hw) container_of(_hw, struct clk_pll, hw) + +/* Helper macros for PLL_VT8500 */ +#define VT8500_PLL_MUL(x) ((x & 0x1F) << 1) +#define VT8500_PLL_DIV(x) ((x & 0x100) ? 1 : 2) + +#define VT8500_BITS_TO_FREQ(r, m, d) \ + ((r / d) * m) + +#define VT8500_BITS_TO_VAL(m, d) \ + ((d == 2 ? 0 : 0x100) | ((m >> 1) & 0x1F)) + +/* Helper macros for PLL_WM8650 */ +#define WM8650_PLL_MUL(x) (x & 0x3FF) +#define WM8650_PLL_DIV(x) (((x >> 10) & 7) * (1 << ((x >> 13) & 3))) + +#define WM8650_BITS_TO_FREQ(r, m, d1, d2) \ + (r * m / (d1 * (1 << d2))) + +#define WM8650_BITS_TO_VAL(m, d1, d2) \ + ((d2 << 13) | (d1 << 10) | (m & 0x3FF)) + +/* Helper macros for PLL_WM8750 */ +#define WM8750_PLL_MUL(x) (((x >> 16) & 0xFF) + 1) +#define WM8750_PLL_DIV(x) ((((x >> 8) & 1) + 1) * (1 << (x & 7))) + +#define WM8750_BITS_TO_FREQ(r, m, d1, d2) \ + (r * (m+1) / ((d1+1) * (1 << d2))) + +#define WM8750_BITS_TO_VAL(f, m, d1, d2) \ + ((f << 24) | ((m - 1) << 16) | ((d1 - 1) << 8) | d2) + +/* Helper macros for PLL_WM8850 */ +#define WM8850_PLL_MUL(x) ((((x >> 16) & 0x7F) + 1) * 2) +#define WM8850_PLL_DIV(x) ((((x >> 8) & 1) + 1) * (1 << (x & 3))) + +#define WM8850_BITS_TO_FREQ(r, m, d1, d2) \ + (r * ((m + 1) * 2) / ((d1+1) * (1 << d2))) + +#define WM8850_BITS_TO_VAL(m, d1, d2) \ + ((((m / 2) - 1) << 16) | ((d1 - 1) << 8) | d2) + +static int vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate, + u32 *multiplier, u32 *prediv) +{ + unsigned long tclk; + + /* sanity check */ + if ((rate < parent_rate * 4) || (rate > parent_rate * 62)) { + pr_err("%s: requested rate out of range\n", __func__); + *multiplier = 0; + *prediv = 1; + return -EINVAL; + } + if (rate <= parent_rate * 31) + /* use the prediv to double the resolution */ + *prediv = 2; + else + *prediv = 1; + + *multiplier = rate / (parent_rate / *prediv); + tclk = (parent_rate / *prediv) * *multiplier; + + if (tclk != rate) + pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, + rate, tclk); + + return 0; +} + +/* + * M * parent [O1] => / P [O2] => / D [O3] + * Where O1 is 900MHz...3GHz; + * O2 is 600MHz >= (M * parent) / P >= 300MHz; + * M is 36...120 [25MHz parent]; D is 1 or 2 or 4 or 8. + * Possible ranges (O3): + * D = 8: 37,5MHz...75MHz + * D = 4: 75MHz...150MHz + * D = 2: 150MHz...300MHz + * D = 1: 300MHz...600MHz + */ +static int wm8650_find_pll_bits(unsigned long rate, + unsigned long parent_rate, u32 *multiplier, u32 *divisor1, + u32 *divisor2) +{ + unsigned long O1, min_err, rate_err; + + if (!parent_rate || (rate < 37500000) || (rate > 600000000)) + return -EINVAL; + + *divisor2 = rate <= 75000000 ? 3 : rate <= 150000000 ? 2 : + rate <= 300000000 ? 1 : 0; + /* + * Divisor P cannot be calculated. Test all divisors and find where M + * will be as close as possible to the requested rate. + */ + min_err = ULONG_MAX; + for (*divisor1 = 5; *divisor1 >= 3; (*divisor1)--) { + O1 = rate * *divisor1 * (1 << (*divisor2)); + rate_err = O1 % parent_rate; + if (rate_err < min_err) { + *multiplier = O1 / parent_rate; + if (rate_err == 0) + return 0; + + min_err = rate_err; + } + } + + if ((*multiplier < 3) || (*multiplier > 1023)) + return -EINVAL; + + pr_warn("%s: rate error is %lu\n", __func__, min_err); + + return 0; +} + +static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1) +{ + /* calculate frequency (MHz) after pre-divisor */ + u32 freq = (parent_rate / 1000000) / (divisor1 + 1); + + if ((freq < 10) || (freq > 200)) + pr_warn("%s: PLL recommended input frequency 10..200Mhz (requested %d Mhz)\n", + __func__, freq); + + if (freq >= 166) + return 7; + else if (freq >= 104) + return 6; + else if (freq >= 65) + return 5; + else if (freq >= 42) + return 4; + else if (freq >= 26) + return 3; + else if (freq >= 16) + return 2; + else if (freq >= 10) + return 1; + + return 0; +} + +static int wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, + u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2) +{ + u32 mul; + int div1, div2; + unsigned long tclk, rate_err, best_err; + + best_err = (unsigned long)-1; + + /* Find the closest match (lower or equal to requested) */ + for (div1 = 1; div1 >= 0; div1--) + for (div2 = 7; div2 >= 0; div2--) + for (mul = 0; mul <= 255; mul++) { + tclk = parent_rate * (mul + 1) / ((div1 + 1) * (1 << div2)); + if (tclk > rate) + continue; + /* error will always be +ve */ + rate_err = rate - tclk; + if (rate_err == 0) { + *filter = wm8750_get_filter(parent_rate, div1); + *multiplier = mul; + *divisor1 = div1; + *divisor2 = div2; + return 0; + } + + if (rate_err < best_err) { + best_err = rate_err; + *multiplier = mul; + *divisor1 = div1; + *divisor2 = div2; + } + } + + if (best_err == (unsigned long)-1) { + pr_warn("%s: impossible rate %lu\n", __func__, rate); + return -EINVAL; + } + + /* if we got here, it wasn't an exact match */ + pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, + rate - best_err); + + *filter = wm8750_get_filter(parent_rate, *divisor1); + + return 0; +} + +static int wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, + u32 *multiplier, u32 *divisor1, u32 *divisor2) +{ + u32 mul; + int div1, div2; + unsigned long tclk, rate_err, best_err; + + best_err = (unsigned long)-1; + + /* Find the closest match (lower or equal to requested) */ + for (div1 = 1; div1 >= 0; div1--) + for (div2 = 3; div2 >= 0; div2--) + for (mul = 0; mul <= 127; mul++) { + tclk = parent_rate * ((mul + 1) * 2) / + ((div1 + 1) * (1 << div2)); + if (tclk > rate) + continue; + /* error will always be +ve */ + rate_err = rate - tclk; + if (rate_err == 0) { + *multiplier = mul; + *divisor1 = div1; + *divisor2 = div2; + return 0; + } + + if (rate_err < best_err) { + best_err = rate_err; + *multiplier = mul; + *divisor1 = div1; + *divisor2 = div2; + } + } + + if (best_err == (unsigned long)-1) { + pr_warn("%s: impossible rate %lu\n", __func__, rate); + return -EINVAL; + } + + /* if we got here, it wasn't an exact match */ + pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, + rate - best_err); + + return 0; +} + +static int vtwm_pll_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_pll *pll = to_clk_pll(hw); + u32 filter, mul, div1, div2; + u32 pll_val; + unsigned long flags = 0; + int ret; + + /* sanity check */ + + switch (pll->type) { + case PLL_TYPE_VT8500: + ret = vt8500_find_pll_bits(rate, parent_rate, &mul, &div1); + if (!ret) + pll_val = VT8500_BITS_TO_VAL(mul, div1); + break; + case PLL_TYPE_WM8650: + ret = wm8650_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); + if (!ret) + pll_val = WM8650_BITS_TO_VAL(mul, div1, div2); + break; + case PLL_TYPE_WM8750: + ret = wm8750_find_pll_bits(rate, parent_rate, &filter, &mul, &div1, &div2); + if (!ret) + pll_val = WM8750_BITS_TO_VAL(filter, mul, div1, div2); + break; + case PLL_TYPE_WM8850: + ret = wm8850_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); + if (!ret) + pll_val = WM8850_BITS_TO_VAL(mul, div1, div2); + break; + default: + pr_err("%s: invalid pll type\n", __func__); + ret = -EINVAL; + } + + if (ret) + return ret; + + spin_lock_irqsave(pll->lock, flags); + + vt8500_pmc_wait_busy(); + writel(pll_val, pll->reg); + vt8500_pmc_wait_busy(); + + spin_unlock_irqrestore(pll->lock, flags); + + return 0; +} + +static long vtwm_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_pll *pll = to_clk_pll(hw); + u32 filter, mul, div1, div2; + long round_rate; + int ret; + + switch (pll->type) { + case PLL_TYPE_VT8500: + ret = vt8500_find_pll_bits(rate, *prate, &mul, &div1); + if (!ret) + round_rate = VT8500_BITS_TO_FREQ(*prate, mul, div1); + break; + case PLL_TYPE_WM8650: + ret = wm8650_find_pll_bits(rate, *prate, &mul, &div1, &div2); + if (!ret) + round_rate = WM8650_BITS_TO_FREQ(*prate, mul, div1, div2); + break; + case PLL_TYPE_WM8750: + ret = wm8750_find_pll_bits(rate, *prate, &filter, &mul, &div1, &div2); + if (!ret) + round_rate = WM8750_BITS_TO_FREQ(*prate, mul, div1, div2); + break; + case PLL_TYPE_WM8850: + ret = wm8850_find_pll_bits(rate, *prate, &mul, &div1, &div2); + if (!ret) + round_rate = WM8850_BITS_TO_FREQ(*prate, mul, div1, div2); + break; + default: + ret = -EINVAL; + } + + if (ret) + return ret; + + return round_rate; +} + +static unsigned long vtwm_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_pll *pll = to_clk_pll(hw); + u32 pll_val = readl(pll->reg); + unsigned long pll_freq; + + switch (pll->type) { + case PLL_TYPE_VT8500: + pll_freq = parent_rate * VT8500_PLL_MUL(pll_val); + pll_freq /= VT8500_PLL_DIV(pll_val); + break; + case PLL_TYPE_WM8650: + pll_freq = parent_rate * WM8650_PLL_MUL(pll_val); + pll_freq /= WM8650_PLL_DIV(pll_val); + break; + case PLL_TYPE_WM8750: + pll_freq = parent_rate * WM8750_PLL_MUL(pll_val); + pll_freq /= WM8750_PLL_DIV(pll_val); + break; + case PLL_TYPE_WM8850: + pll_freq = parent_rate * WM8850_PLL_MUL(pll_val); + pll_freq /= WM8850_PLL_DIV(pll_val); + break; + default: + pll_freq = 0; + } + + return pll_freq; +} + +static const struct clk_ops vtwm_pll_ops = { + .round_rate = vtwm_pll_round_rate, + .set_rate = vtwm_pll_set_rate, + .recalc_rate = vtwm_pll_recalc_rate, +}; + +static __init void vtwm_pll_clk_init(struct device_node *node, int pll_type) +{ + u32 reg; + struct clk_hw *hw; + struct clk_pll *pll_clk; + const char *clk_name = node->name; + const char *parent_name; + struct clk_init_data init; + int rc; + + if (!pmc_base) + vtwm_set_pmc_base(); + + rc = of_property_read_u32(node, "reg", ®); + if (WARN_ON(rc)) + return; + + pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL); + if (WARN_ON(!pll_clk)) + return; + + pll_clk->reg = pmc_base + reg; + pll_clk->lock = &_lock; + pll_clk->type = pll_type; + + of_property_read_string(node, "clock-output-names", &clk_name); + + init.name = clk_name; + init.ops = &vtwm_pll_ops; + init.flags = 0; + parent_name = of_clk_get_parent_name(node, 0); + init.parent_names = &parent_name; + init.num_parents = 1; + + pll_clk->hw.init = &init; + + hw = &pll_clk->hw; + rc = clk_hw_register(NULL, &pll_clk->hw); + if (WARN_ON(rc)) { + kfree(pll_clk); + return; + } + rc = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw); + clk_hw_register_clkdev(hw, clk_name, NULL); +} + + +/* Wrappers for initialization functions */ + +static void __init vt8500_pll_init(struct device_node *node) +{ + vtwm_pll_clk_init(node, PLL_TYPE_VT8500); +} +CLK_OF_DECLARE(vt8500_pll, "via,vt8500-pll-clock", vt8500_pll_init); + +static void __init wm8650_pll_init(struct device_node *node) +{ + vtwm_pll_clk_init(node, PLL_TYPE_WM8650); +} +CLK_OF_DECLARE(wm8650_pll, "wm,wm8650-pll-clock", wm8650_pll_init); + +static void __init wm8750_pll_init(struct device_node *node) +{ + vtwm_pll_clk_init(node, PLL_TYPE_WM8750); +} +CLK_OF_DECLARE(wm8750_pll, "wm,wm8750-pll-clock", wm8750_pll_init); + +static void __init wm8850_pll_init(struct device_node *node) +{ + vtwm_pll_clk_init(node, PLL_TYPE_WM8850); +} +CLK_OF_DECLARE(wm8850_pll, "wm,wm8850-pll-clock", wm8850_pll_init); |