diff options
Diffstat (limited to 'drivers/clk/clk-twl6040.c')
| -rw-r--r-- | drivers/clk/clk-twl6040.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/clk/clk-twl6040.c b/drivers/clk/clk-twl6040.c new file mode 100644 index 000000000..4bd1b32a4 --- /dev/null +++ b/drivers/clk/clk-twl6040.c @@ -0,0 +1,177 @@ +/* +* TWL6040 clock module driver for OMAP4 McPDM functional clock +* +* Copyright (C) 2012 Texas Instruments Inc. +* Peter Ujfalusi <peter.ujfalusi@ti.com> +* +* This program is free software; you can redistribute it and/or +* modify it under the terms of the GNU General Public License +* version 2 as published by the Free Software Foundation. +* +* 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. +* +* You should have received a copy of the GNU General Public License +* along with this program; if not, write to the Free Software +* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA +* 02110-1301 USA +* +*/ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/mfd/twl6040.h> +#include <linux/clk-provider.h> + +struct twl6040_pdmclk { + struct twl6040 *twl6040; + struct device *dev; + struct clk_hw pdmclk_hw; + int enabled; +}; + +static int twl6040_pdmclk_is_prepared(struct clk_hw *hw) +{ + struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, + pdmclk_hw); + + return pdmclk->enabled; +} + +static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk, + unsigned int reg) +{ + const u8 reset_mask = TWL6040_HPLLRST; /* Same for HPPLL and LPPLL */ + int ret; + + ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask); + if (ret < 0) + return ret; + + ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask); + if (ret < 0) + return ret; + + return 0; +} + +/* + * TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At + * Cold Temperature". This affects cold boot and deeper idle states it + * seems. The workaround consists of resetting HPPLL and LPPLL. + */ +static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk) +{ + int ret; + + ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL); + if (ret) + return ret; + + ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL); + if (ret) + return ret; + + return 0; +} + +static int twl6040_pdmclk_prepare(struct clk_hw *hw) +{ + struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, + pdmclk_hw); + int ret; + + ret = twl6040_power(pdmclk->twl6040, 1); + if (ret) + return ret; + + ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk); + if (ret) + goto out_err; + + pdmclk->enabled = 1; + + return 0; + +out_err: + dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret); + twl6040_power(pdmclk->twl6040, 0); + + return ret; +} + +static void twl6040_pdmclk_unprepare(struct clk_hw *hw) +{ + struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, + pdmclk_hw); + int ret; + + ret = twl6040_power(pdmclk->twl6040, 0); + if (!ret) + pdmclk->enabled = 0; + +} + +static unsigned long twl6040_pdmclk_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, + pdmclk_hw); + + return twl6040_get_sysclk(pdmclk->twl6040); +} + +static const struct clk_ops twl6040_pdmclk_ops = { + .is_prepared = twl6040_pdmclk_is_prepared, + .prepare = twl6040_pdmclk_prepare, + .unprepare = twl6040_pdmclk_unprepare, + .recalc_rate = twl6040_pdmclk_recalc_rate, +}; + +static const struct clk_init_data twl6040_pdmclk_init = { + .name = "pdmclk", + .ops = &twl6040_pdmclk_ops, + .flags = CLK_GET_RATE_NOCACHE, +}; + +static int twl6040_pdmclk_probe(struct platform_device *pdev) +{ + struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent); + struct twl6040_pdmclk *clkdata; + int ret; + + clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL); + if (!clkdata) + return -ENOMEM; + + clkdata->dev = &pdev->dev; + clkdata->twl6040 = twl6040; + + clkdata->pdmclk_hw.init = &twl6040_pdmclk_init; + ret = devm_clk_hw_register(&pdev->dev, &clkdata->pdmclk_hw); + if (ret) + return ret; + + platform_set_drvdata(pdev, clkdata); + + return of_clk_add_hw_provider(pdev->dev.parent->of_node, + of_clk_hw_simple_get, + &clkdata->pdmclk_hw); +} + +static struct platform_driver twl6040_pdmclk_driver = { + .driver = { + .name = "twl6040-pdmclk", + }, + .probe = twl6040_pdmclk_probe, +}; + +module_platform_driver(twl6040_pdmclk_driver); + +MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock"); +MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>"); +MODULE_ALIAS("platform:twl6040-pdmclk"); +MODULE_LICENSE("GPL"); |