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(p200300C6EBDC400005E3F718F7C909EF.dip0.t-ipconnect.de. [2003:c6:ebdc:4000:5e3:f718:f7c9:9ef]) by smtp.googlemail.com with ESMTPSA id s18sm17020662wmb.18.2017.03.14.14.54.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 14 Mar 2017 14:54:24 -0700 (PDT) From: Heiner Kallweit Subject: [PATCH v4 05/10] i2c: meson: use full 12 bits for clock divider To: Wolfram Sang , Jerome Brunet , Kevin Hilman References: <1a2ecdc8-a326-a7a7-22ec-658fd147daf4@gmail.com> Message-ID: Date: Tue, 14 Mar 2017 22:51:30 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1a2ecdc8-a326-a7a7-22ec-658fd147daf4@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170314_145447_533722_1583751A X-CRM114-Status: UNSURE ( 9.07 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-amlogic@lists.infradead.org, "linux-i2c@vger.kernel.org" Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+patchwork-linux-amlogic=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The clock divider has 12 bits, splitted into a 10 bit field and a 2 bit field. The extra 2 bits aren't used currently. Change this to use the full 12 bits and warn if the requested frequency is too low. Signed-off-by: Heiner Kallweit Acked-by: Jerome Brunet --- v2: - added Acked-by v3: - changed order of patches v4: - no changes --- drivers/i2c/busses/i2c-meson.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c index ac0ac82d..03f70282 100644 --- a/drivers/i2c/busses/i2c-meson.c +++ b/drivers/i2c/busses/i2c-meson.c @@ -35,7 +35,9 @@ #define REG_CTRL_STATUS BIT(2) #define REG_CTRL_ERROR BIT(3) #define REG_CTRL_CLKDIV_SHIFT 12 -#define REG_CTRL_CLKDIV_MASK ((BIT(10) - 1) << REG_CTRL_CLKDIV_SHIFT) +#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12) +#define REG_CTRL_CLKDIVEXT_SHIFT 28 +#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28) #define I2C_TIMEOUT_MS 500 @@ -134,8 +136,15 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq) unsigned int div; div = DIV_ROUND_UP(clk_rate, freq * 4); + + /* clock divider has 12 bits */ + WARN_ON(div >= (1 << 12)); + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK, - div << REG_CTRL_CLKDIV_SHIFT); + (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT); + + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK, + (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT); dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__, clk_rate, freq, div);